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Are Toll-like receptors (TLRs) induced by microbes? | Yes,
Gram-negative bacteria and endogenous molecules coordinate to trigger inflammatory cascades via Toll-like receptor 4 to induce excessive expression of cytokines such as tumor necrosis factor-α and to activate NLRP3 inflammasome, a multiprotein complex that processes pro-interleukin-1β into its mature form. | Host-directed therapies are gaining considerable impetus because of the
emergence of drug-resistant strains of pathogens due to antibiotic therapy.
Therefore, there is an urgent need to exploit alternative and novel strategies
directed at host molecules to successfully restrict infections. The C-type
lectin receptor CLEC4E and Toll-like receptor TLR4 expressed by host cells are
among the first line of defense in encountering pathogens. Therefore, we
exploited signaling of macrophages through CLEC4E in association with TLR4
agonists (C4.T4) to control the growth of Mycobacterium tuberculosis (Mtb). We
observed significant improvement in host immunity and reduced bacterial load in
the lungs of Mtb-infected mice and guinea pigs treated with C4.T4 agonists.
Further, intracellular killing of Mtb was achieved with a 10-fold lower dose of
isoniazid or rifampicin in conjunction with C4.T4 than the drugs alone. C4.T4
activated MYD88, PtdIns3K, STAT1 and RELA/NFKB, increased lysosome biogenesis,
decreased Il10 and Il4 gene expression and enhanced macroautophagy/autophagy.
Macrophages from autophagy-deficient (atg5 knockout or Becn1 knockdown) mice
showed elevated survival of Mtb. The present findings also unveiled the novel
role of CLEC4E in inducing autophagy through MYD88, which is required for
control of Mtb growth. This study suggests a unique immunotherapeutic approach
involving CLEC4E in conjunction with TLR4 to restrict the survival of Mtb
through autophagy.
ABBREVIATIONS: 3MA: 3 methyladenine; AO: acridine orange; Atg5: autophagy
related 5; AVOs: acidic vesicular organelles; BECN1: beclin 1, autophagy
related; BMDMs: bone marrow derived macrophages; bw: body weight; C4.T4:
agonists of CLEC4E (C4/TDB) and TLR4 (T4/ultra-pure-LPS); CFU: colony forming
unit; CLEC4E/Mincle: C-type lectin domain family 4, member e; CLR: c-type lectin
receptor; INH: isoniazid; LAMP1: lysosomal-associated membrane protein 1;
MφC4.T4: Mtb-infected C4.T4 stimulated macrophages; MAP1LC3/LC3:
microtubule-associated protein 1 light chain 3; MDC: monodansylcadaverine; MTOR:
mechanistic target of rapamycin kinase; MYD88: myeloid differentiation primary
response 88; NFKB: nuclear factor of kappa light polypeptide gene enhance in B
cells; NLR: NOD (nucleotide-binding oligomerization domain)-like receptors; PFA:
paraformaldehyde; PPD: purified protein derivative; PtdIns3K: class III
phosphatidylinositol 3-kinase; RELA: v-rel reticuloendotheliosis viral oncogene
homolog A (avian); RIF: rifampicin; RLR: retinoic acid-inducible gene-I-like
receptors; TDB: trehalose-6,6´-dibehenate; TLR4: toll-like receptor 4;
Ultra-pure-LPS: ultra-pure lipopolysaccharide-EK; V-ATPase: vacuolar-type H+
ATPase. During viral infection, viral nucleic acids are detected by virus sensor
proteins including toll-like receptor 3 or retinoic acid-inducible gene I-like
receptors (RLRs) in mammalian cells. Activation of these virus sensor proteins
induces type-I interferon production and represses viral replication. Recently,
we reported that an RLR family member, laboratory of genetics and physiology 2
(LGP2), modulates RNA silencing by interacting with an RNA silencing enhancer,
TAR-RNA binding protein (TRBP). However, the biological implications remained
unclear. Here, we show that LGP2 enhances apoptosis by upregulating apoptosis
regulatory genes during viral infection. Sendai virus (SeV) infection increased
LGP2 expression approximately 900 times compared to that in non-virus-infected
cells. Then, the induced LGP2 interacted with TRBP, resulting in the inhibition
of maturation of the TRBP-bound microRNA (miRNA) and its subsequent RNA
silencing activity. Gene expression profiling revealed that apoptosis regulatory
genes were upregulated during SeV infection: caspases-2, -8, -3 and -7, four
cysteine proteases with key roles in apoptosis, were upregulated directly or
indirectly through the repression of a typical TRBP-bound miRNA, miR-106b. Our
findings may shed light on the mechanism of apoptosis, induced by the TRBP-bound
miRNAs through the interaction of TRBP with LGP2, as an antiviral defense system
in mammalian cells. Recent advances in small-bowel endoscopy such as capsule endoscopy have shown
that non-steroidal anti-inflammatory drugs (NSAIDs) frequently damage the small
intestine, with the prevalence rate of mucosal breaks of around 50% in chronic
users. A significant proportion of patients with NSAIDs-induced enteropathy are
asymptomatic, but some patients develop symptomatic or complicated ulcers that
need therapeutic intervention. Both inhibition of prostaglandins due to the
inhibition of cyclooxygenases and mitochondrial dysfunction secondary to the
topical effect of NSAIDs play a crucial role in the early process of injury. As
a result, the intestinal barrier function is impaired, which allows
enterobacteria to invade the mucosa. Gram-negative bacteria and endogenous
molecules coordinate to trigger inflammatory cascades via Toll-like receptor 4
to induce excessive expression of cytokines such as tumor necrosis factor-α and
to activate NLRP3 inflammasome, a multiprotein complex that processes
pro-interleukin-1β into its mature form. Finally, neutrophils accumulate in the
mucosa, resulting in intestinal ulceration. Currently, misoprostol is the only
drug that has a proven beneficial effect on bleeding small intestinal ulcers
induced by NSAIDs or low-dose aspirin, but its protection is insufficient.
Therefore, the efficacy of the combination of misoprostol with other drugs,
especially those targeting the innate immune system, should be assessed in the
next step. Author information:
(1)Department of Pathology, University of Cambridge, Cambridge, UK.
(2)Centre for Trophoblast Research, Departments of Physiology and Neuroscience,
University of Cambridge, Cambridge, UK.
(3)Singapore Immunology Network, Agency for Science, Technology and Research,
Singapore, Singapore.
(4)School of Biological Sciences, Nanyang Technological University, Singapore,
Singapore.
(5)Key Laboratory for Regenerative Medicine of Ministry of Education, Institute
of Hematology, School of Medicine, Ji University, Guangzhou, China.
(6)State Key Laboratory of Proteomics, Academy of Military Medical Sciences,
Academy of Military Sciences, Beijing, China.
(7)State Key Laboratory of Experimental Hematology, Institute of Hematology and
Blood Diseases Hospital, Chinese Academy of Medical Sciences, Tianjin, China.
(8)Shanghai Institute of Immunology, Shanghai JiaoTong University School of
Medicine, Shanghai, China.
(9)Translational Immunology Institute, SingHealth Duke-NUS Academic Medical
Centre, Singapore, Singapore.
(10)Department of Genetics, University of Cambridge, Cambridge, UK. |
What is a decoy exosome? | exosomes display a large repertoire of tumor antigens that induce autoantibodies and exert a decoy function against complement-mediated cytotoxicity. | Immune evasion from NK surveillance related to inadequate NK-cell function has
been suggested as an explanation of the high incidence of relapse and fatal
outcome of many blood maligcies. In this report we have used Jurkat and Raji
cell lines as a model for studies of the NKG2D receptor-ligand system in T-and B
cell leukemia/lymphoma. Using real-time quantitative RT-PCR and immunoflow
cytometry we show that Jurkat and Raji cells constitutively express mRNA and
protein for the stress-inducible NKG2D ligands MICA/B and ULBP1 and 2, and
up-regulate the expression in a cell-line specific and stress-specific manner.
Furthermore, we revealed by electron microscopy, immunoflow cytometry and
western blot that these ligands were expressed and secreted on exosomes,
ometer-sized microvesicles of endosomal origin. Acting as a decoy, the NKG2D
ligand-bearing exosomes downregulate the in vitro NKG2D receptor-mediated
cytotoxicity and thus impair NK-cell function. Interestingly, thermal and
oxidative stress enhanced the exosome secretion generating more soluble NKG2D
ligands that aggravated the impairment of the cytotoxic response. Taken
together, our results might partly explain the clinically observed NK-cell
dysfunction in patients suffering from leukemia/lymphoma. The adverse effect of
thermal and oxidative stress, enhancing the release of immunosuppressive
exosomes, should be considered when cytostatic and hyperthermal anti-cancer
therapies are designed. Mesenchymal stem cells (MSCs) derived exosomes have been shown to have
protective effects on the kidney in ischemia/reperfusion-induced renal injury.
However, the key components in the exosomes and their potential mechanisms for
the kidney protective effects are not well understood. In our current study, we
focused on the abundant proteins in exosomes derived from MSCs (MSC-exo) and
found that the C-C motif chemokine receptor-2 (CCR2) was expressed on MSC-exo
with a high ability to bind to its ligand CCL2. We also proved that CCR2
high-expressed MSC-exo could reduce the concentration of free CCL2 and suppress
its functions to recruit or activate macrophage. Further, knockdown of CCR2
expression on the MSC-exo greatly abolished these effects. Finally, we also
found that CCR2 knockdown impaired the protective effects of MSC-exo for the
renal ischemia/reperfusion injury in mouse. The results indicate that CCR2
expressed on MSC-exo may play a key role in inflammation regulation and renal
injury repair by acting as a decoy to suppress CCL2 activity. Our study may cast
new light on understanding the functions of the MSC-exo and these receptor
proteins expressed on exosomes. |
Can you summarize Myasthenia Gravis? | Myasthenia gravis (MG) is a neuromuscular disease which affects the central nervous system, dorsal root ganglia of the spinal cord, heart and in certain cases the pancreas. Two thirds of MG cases result from sporadic genetic mutations, not inheritance, but their offspring may inherit it from them. | Myasthenia gravis is a common autoimmune disorder characterized by the presence
of pathogenic antibodies directed against the acetylcholine receptor. Patients
present with variable degrees and distribution of fluctuating weakness at times
life threatening. Clinical manifestations, establishment of diagnosis, the
natural history of myasthenia gravis, and therapeutic options are herein
reviewed. Far less common is Lambert-Eaton syndrome (the myasthenic syndrome),
another autoimmune disorder due to the presence of antibodies directed against
the PQ-type voltage-gated calcium channels. Clinical features and treatment
options are summarized. Myasthenia gravis is a chronic neuromuscular disease characterized by muscular
weakness and fatigability. Dental management of patients diagnosed with
myasthenia gravis presents a challenge to the dental profession. A MEDLINE
search of the English medical (limited to provision in dental care) and dental
literature on myasthenia gravis and dental management published between 1975 and
2004 was conducted. In the dental literature, 12 articles were found, and only a
few focused on myasthenia gravis and dental care. The purpose of this article
was to review and summarize the clinical signs and symptoms associated with
myasthenia gravis, highlighting the role of the dental profession in the process
of the diagnosis and management of the oral and dental complications that might
be associated with the disease, while avoiding myasthenic crisis. PURPOSE OF REVIEW: Some of the 20% of myasthenia gravis patients who do not have
antibodies to acetylcholine receptors (AChRs) have antibodies to muscle specific
kinase (MuSK), but a full understanding of their frequency, the associated
clinical phenotype and the mechanisms of action of the antibodies has not yet
been achieved. Moreover, some patients do not respond well to conventional
corticosteroid therapy. Here we review recent clinical and experimental studies
on MuSK antibody associated myasthenia gravis, and summarize the results of
newer treatments for myasthenia gravis.
RECENT FINDINGS: MuSK antibodies are found in a variable proportion of AChR
antibody negative myasthenia gravis patients who are often, but not exclusively,
young adult females, with bulbar, neck, or respiratory muscle weakness. The
thymus histology is normal or only very mildly abnormal. Surprisingly, limb or
intercostal muscle biopsies exhibit no reduction in AChR numbers or complement
deposition. However, patients without AChR or MuSK antibodies appear to be
similar to those with AChR antibodies and may have low-affinity AChR antibodies.
A variety of treatments, often intended to enable corticosteroid doses to be
reduced, have been used in all types of myasthenia gravis with some success, but
they have not been subjected to randomized clinical trials.
SUMMARY: MuSK antibodies define a form of myasthenia gravis that can be
difficult to diagnose, can be life threatening and may require additional
treatments. An improved AChR antibody assay may be helpful in patients without
AChR or MuSK antibodies. Clinical trials of drugs in other neuroimmunological
diseases may help to guide the treatment of myasthenia gravis. Myasthenia gravis is a rare, auto-immune neuromuscular junction disorder.
Prevalence rates is about 50/1,000000. The disease results from circulating
auto-antibody attacks against post-synaptic targets (acetylcholine receptor
[AChR] in 80% cases) on the endplate region of the postsynaptic membrane. The
diagnosis is supported clinically by transient weakness, increased by activity
that can affect eye movements, swallowing, speech, upper and lower limbs, and
trunk. There are generalized or focalized forms (as ocular myasthenia). The
course is variable and evolved either with attacks or more chronically. Helpful
tests for diagnosis are serologic antibodies detection against AChR, decrement
of muscle action potential after repetitive nerve stimulations, identification
of thymus gland abnormality (frequently associated with myasthenia) by chest
computed tomography. Myasthenia gravis treatment is based on oral form of
cholinesterase inhibitors, corticosteroids and other immunosuppressive drugs in
severe forms. During myasthenia crisis, intraveinous immune globulines or plasma
exchanges can be used. Thymectomy is proposed in case of thymus abnormality. Myasthenia gravis is an autoimmune neuromuscular disorder characterized by
skeletal muscle involvement, causing muscle weakness and fatigue. The prevalence
of the disease is approximately 1:7500 with a maximal prevalence during the
second and third decade in women and the fifth and sixth decade in men, although
it may appear at any age. The disease has a slight female preponderance, with a
sex ratio of 3:2. Cardiac involvement in myasthenia gravis may take several
forms, ranging from asymptomatic ECG changes to ventricular tachycardia,
myocarditis, conduction disorders, heart failure and sudden death. We hereby
report two cases of patients with myasthenia gravis who developed signs and
symptoms of cardiovascular involvement, requiring admission in a cardiology ward
for further investigation and treatment. The particular characteristics of the
first case may be summarized by the symptomatic conduction disturbances with
frequent episodes of syncope in a patient with myasthenia gravis who
necessitated permanent pacing and the difficulties we encountered in the
establishment of conduction disturbancies etiology (due to the disease or due to
the treatment with acetylcolinesterase inhibitors). The second case shows a
different kind of cardiac involvement in myasthenia gravis--the ECG changes
(giant diffuse T waves in a patient with cardiovascular risk factors) which
needed further investigation and long term surveillance. Myasthenia Gravis is an organ-specific autoimmune disorder generaly thought to
be caused by an antibody-mediated attack against the skeletal muscle nicotinic
acetylcholine receptor (AChR) at the neuromuscular junction. Not infrequently
there may be other diseases accompanying myasthenia, that can give different
neuro-ophtalmological manifestations or neurological syndromes with autoimmune
substrate. By these autoimmmune diseases we note:Autoimmune thyroiditis,
Systemic lupus erythematous, Dermatomyositis, i.e. The extraocular muscle
weakness is present at 90% of myastenia patients. While anti-AChR are detectable
in the majority of patients with generalized myasthenia, at patients with ocular
myasthenia these antibodies are nearly undetectable. On the another hand,
epidemiological, clinical and immunoserological studies, suggests that the
ocular myasthenia and generalized myasthenia are two separate disorders. Both
Myasthenia Gravis forms could be associated with other autoimmune disturbances
with ocular impact, for example such as Autoimmune thyroiditis Ophtalmopathy. PURPOSE OF REVIEW: Juvenile myasthenia gravis is a relatively rare autoimmune
neuromuscular disorder. The pathophysiology of juvenile myasthenia gravis is
similar to that of adult myasthenia gravis, though there remain important
differences regarding presentation and therapeutic options. We review the
pathophysiology, clinical presentation, and treatment options for juvenile
myasthenia gravis.
RECENT FINDINGS: Randomized clinical studies of myasthenia gravis have been
carried out primarily in adult populations. As juvenile myasthenia gravis is
rare, it has been difficult to collect prospective randomized controlled data to
evaluate treatment outcomes and efficacy. A recent retrospective series suggests
that, as in adult myasthenia gravis, thymectomy is a viable therapeutic option
for selected cases of generalized juvenile myasthenia gravis. This is
corroborated by the clinical experience of the authors in a referral center with
a cohort of patients affected by juvenile myasthenia gravis over a number of
years.
SUMMARY: Recent studies illustrate that some, but not all, adult research on
myasthenia gravis is applicable to children and adolescents with juvenile
myasthenia gravis. Adult research can inform pediatric studies, but should not
be regarded as a substitute for dedicated research in those populations. Myasthenia gravis is the most frequent acquired disorder of neuromuscular
transmission. In the majority of cases, pathogenic antibodies against components
of the postsynaptic muscle endplate membrane can be detected. In recent years
there have been significant advances in the pathophysiological understanding and
therapy of the disease. Areas covered: PubMed searches were conducted for the
term 'myasthenia gravis' cross-referenced with the terms 'immunology',
'subgroups', 'antibody', 'ocular', 'thymoma', 'treatment' and 'thymectomy'.
Additionally, we summarized the current state of immunopathology and therapy.
Expert commentary: Immunological research defined new target antigens at the
postsynaptic neuromuscular junction which along with clinical features allow a
refined definition of disease subgroups. Overall the prognosis of myasthenia
gravis with best possible symptomatic, immunosuppressive and supportive
treatment is good but new immunomodulatory treatment options are developed for
patients who do not respond well to the first line therapy. For most patients
individually adapted long-term drug therapy is needed. PURPOSE OF REVIEW: Myasthenia gravis, a rare disorder of the neuromuscular
transmission, is increasingly acknowledged as a syndrome more than as a single
disease. This review summarizes recent advances in pathophysiology which confirm
the disease heterogeneity, and may help find disease-targeted and
patient-targeted therapies.
RECENT FINDINGS: Antibodies to the acetylcholine receptor, the muscle-specific
tyrosine kinase and the lipoprotein receptor protein 4, characterize disease
subtypes with distinct clinical traits and immune-pathogenic mechanisms.
Genome-wide approaches have identified susceptibility loci within genes that
participate in the immune response. Regulatory T and B cells appear to be
defective in myasthenia gravis. In patients with acetylcholine receptor
antibodies, thymectomy associated with prednisone proved more effective than
prednisone alone in a multicenter randomized trial. New therapeutic options
target B cells, B-cell growth factors and complement inhibition, and are
currently reserved for patients with refractory disease.
SUMMARY: In the recent past, there has been an active search for new antigens in
myasthenia gravis, whereas clinical and experimental studies have provided new
insights of crucial pathways in immune regulation, which might become the
targets of future therapeutic interventions. BACKGROUND: Myasthenia gravis is a rare autoimmune neuromuscular disorder. The
disorder requires long-term use of expensive medication to control clinical
symptoms. This study analyzed the change in trends of total medical expenses and
out-of-pocket expenses for patients with myasthenia gravis and explored the
factors influencing them.
METHODS: In this retrospective study, data were derived from a survey of medical
service utilization for patients insured by the Urban Basic Medical Insurance in
China from 2013 to 2015. The cost data of 3347 patients with myasthenia gravis
were included in this study. The baseline characteristics and medical expenses
for patients with myasthenia gravis were analyzed using a descriptive method.
The difference and influencing factors of the out-of-pocket ratio were analyzed
from both outpatient and inpatient expenses by using the quantile regression
method.
RESULTS: The total expenses reimbursed by the Urban Basic Medicine Insurance for
all patients with myasthenia gravis fell progressively from 73.1 to 58.7% during
the study period. Patients' out-of-pocket expenses increased gradually, of which
expenses within the scope of Basic Medicine Insurance increased from 14.7 to
22.6% and expenses outside of the Basic Medicine Insurance scope increased from
12.6 to 18.7%. Moreover, the panel quantile results showed a positive
correlation between the year of receiving treatment and the out-of-pocket ratio.
In addition to the 25th quantile of the out-of-pocket ratio among outpatients
with myasthenia gravis, there were significant differences in medical insurance
and medical institution among all the other quantiles. Significant regional
differences were found in all quantiles of the out-of-pocket ratio, except for
the 75th quantile among inpatients. Lastly, age had a negative effect on
inpatients with myasthenia gravis across all quantiles, but not on outpatients.
CONCLUSIONS: From 2013 to 2015, patients with myasthenia gravis's out-of-pocket
expenses increased progressively. Moreover, the individual out-of-pocket ratio
was affected by the year, medical insurance, medical institution, region, and
age. The current medical insurance policy for the general public has a low
ability to cater for patients with myasthenia gravis. Myasthenia gravis is an autoimmune disease in which immunoglobulin G (IgG)
autoantibodies are formed against the nicotinic acetylcholine receptor (AChR) or
other components of the neuromuscular junction. Though effective treatments are
currently available, many commonly used therapies have important limitations and
alternative therapeutic options are needed for patients. A novel treatment
approach currently in clinical trials for myasthenia gravis targets the neonatal
Fc receptor (FcRn). This receptor plays a central role in prolonging the
half-life of IgG molecules. The primary function of FcRn is salvage of IgG and
albumin from lysosomal degradation through the recycling and transcytosis of IgG
within cells. Antagonism of this receptor causes IgG catabolism, resulting in
reduced overall IgG and pathogenic autoantibody levels. This treatment approach
is particularly intriguing as it does not result in widespread immune
suppression, in contrast to many therapies in routine clinical use. Experience
with plasma exchange and emerging phase 2 clinical trial data of FcRn
antagonists provide proof of concept for IgG lowering in myasthenia gravis. Here
we review the IgG lifecycle and the relevance of IgG lowering to myasthenia
gravis treatment and summarize the available data on FcRn targeted therapeutics
in clinical trials for myasthenia gravis. Myasthenia gravis (MG) and Lambert-Eaton myasthenic syndrome (LEMS) are the most
common disorders of neuromuscular transmission in clinical practice. Disorders
of the neuromuscular junction (NMJ) are characterized by fluctuating and
fatigable weakness and include autoimmune, toxic, and genetic conditions. Adults
with NMJ disorders are most often antibody mediated, with MG being the most
common, having a prevalence of approximately 1 in 10,000, and with women being
affected about twice as often as men. This article focuses on advances in
management of autoimmune MG and LEMS. |
What 3 disorders are commonly associated with Kaufman-McKusick syndrome? | McKusick-Kaufman syndrome (MKKS) is a rare, recessively inherited syndrome reported mainly in young children. It is characterised by vaginal atresia with hydrometrocolpos, postaxial polydactyly, and congenital heart defect. | McKusick-Kaufman syndrome is an autosomal recessive multiple malformation
syndrome characterized by hydrometrocolpos and polydactyly. We report on a
patient with McKusick-Kaufman syndrome and severe hydrops. This case illustrates
the necessity of genetic evaluations for all patients with unexplained hydrops. The Kaufman-McKusick syndrome (MK 23670) is a rare autosomal recessive disorder
characterized by the triad of hydrometrocolpos, postaxial polydactyly, and
congenital heart disease. Multiple other anomalies have been ascribed to this
syndrome. Hydrometrocolpos, especially if unrecognized, may be a serious,
life-threatening condition in the newborn girl. Forty-four cases have been so
far reported in the literature. A great phenotypic variability occurs in this
syndrome, therefore making it very difficult to identify the disorder at its
presentation and classify it correctly. We shall hereafter review current data
regarding the prominent clinical features, the diagnosis and treatment of this
syndrome. Problems in genetic counseling will be discussed. The McKusick-Dungy-Kaufman syndrome is characterized by hydrometrocolpos,
polydactyly and congenital heart disease. Two of these 3 main symptoms should be
present for the diagnosis. Associated anomalies are mainly found in the
urogenital tract, the gastro-intestinal tract and the skeletal system. On the
basis of 2 patients and the literature the clinical features and the genetic
aspects of this syndrome are reviewed. The clinical variability and the severity
of the syndrome are stressed. Evidence for an autosomal recessive inheritance is
given. Because of the clinical variability it seems preferable to use the term
complex rather than syndrome. Mucometrocolpos is the distention of the uterus and vagina caused by obstruction
to the drainage of genital secretions. Although most cases of mucometrocolpos
are sporadic, it may be part of an autosomal recessive condition, known as
McKusick-Kaufman syndrome (MKS), including postaxial polydactyly and congenital
heart disease as main findings. The diagnosis may be difficult when the presence
of additional findings creates an overlap with other syndromes. We report on a
female infant with mucometrocolpos, postaxial polydactyly, congenital heart
disease, short limbs, short ribs, and chest constriction. The
clinicopathological findings are described and discussed in the context of the
phenotypic spectrums of MKS and mucometrocolpos concomitant with Ellis van
Creveld syndrome. McKusick-Kaufman syndrome is a human developmental anomaly syndrome comprising
mesoaxial or postaxial polydactyly, congenital heart disease and
hydrometrocolpos. This syndrome is diagnosed most frequently in the Old Order
Amish population and is inherited in an autosomal recessive pattern with reduced
penetrance and variable expressivity. Homozygosity mapping and linkage analyses
were conducted using two pedigrees derived from a larger pedigree published in
1978. The PedHunter software query system was used on the Amish Genealogy
Database to correct the previous pedigree, derive a minimal pedigree connecting
those affected sibships that are in the database and determine the most recent
common ancestors of the affected persons. Whole genome short tandem repeat
polymorphism (STRP) screening showed homozygosity in 20p12, between D20S162 and
D20S894 , an area that includes the Alagille syndrome critical region. The peak
two-point LOD score was 3.33, and the peak three-point LOD score was 5.21. The
physical map of this region has been defined, and additional polymorphic markers
have been isolated. The region includes several genes and expressed sequence
tags (ESTs), including the jagged1 gene that recently has been shown to be
haploinsufficient in the Alagille syndrome. Sequencing of jagged1 in two
unrelated individuals affected with McKusick-Kaufman syndrome has not revealed
any disease-causing mutations. McKusick-Kaufman syndrome (MKKS, MIM 236700) is a human developmental anomaly
syndrome comprising hydrometrocolpos (HMC), postaxial polydactyly (PAP) and
congenital heart disease (CHD). MKKS has been mapped in the Old Order Amish
population to 20p12, between D20S162 and D20S894 (ref. 3). Here we describe the
identification of a gene mutated in MKKS. We analysed the approximately 450-kb
candidate region by sample sequencing, which revealed the presence of several
known genes and EST clusters. We evaluated candidate transcripts by
northern-blot analysis of adult and fetal tissues. We selected one transcript
with widespread expression, MKKS, for analysis in a patient from the Amish
pedigree and a sporadic, non-Amish case. The Old Order Amish patient was found
to be homozygous for an allele that had two missense substitutions and the
non-Amish patient was a compound heterozygote for a frameshift mutation
predicting premature protein truncation and a distinct missense mutation. The
MKKS predicted protein shows amino acid similarity to the chaperonin family of
proteins, suggesting a role for protein processing in limb, cardiac and
reproductive system development. We believe that this is the first description
of a human disorder caused by mutations affecting a putative chaperonin
molecule. McKusick-Kaufman syndrome comprises hydrometrocolpos, polydactyly, and
congenital heart defects and overlaps with Bardet-Biedl syndrome, comprising
retinitis pigmentosa, polydactyly, obesity, mental retardation, and renal and
genital anomalies. Bardet-Biedl syndrome is genetically heterogeneous with three
cloned genes ( BBS2, BBS4, and MKKS) and at least three other known loci ( BBS1,
BBS3, and BBS5). Both McKusick-Kaufman syndrome and Bardet-Biedl syndrome are
inherited in an autosomal recessive pattern, and both syndromes are caused by
mutations in the MKKS gene. However, mutations in MKKS are found in only 4%-11%
of unselected Bardet-Biedl syndrome patients. We hypothesized that an analysis
of patients with atypical Bardet-Biedl syndrome and McKusick-Kaufman syndrome
(Group I; 15 probands) and patients with Bardet-Biedl syndrome who had linkage
results inconsistent with linkage to the other loci (Group II; 12 probands)
could increase the MKKS mutation yield. Both mutant alleles were identified in
only two families in Group II. Single (heterozygous) sequence variations were
found in three Group I families and in two Group II families. Combining these
results with previously published data showed that only one mutant allele was
detected in nearly half of all patients screened to date, suggesting that
unusual mutational mechanisms or patterns of inheritance may be involved.
However, sequencing of the BBS2 gene in these patients did not provide any
evidence of digenic or "triallelic" inheritance. The frequency of detected
mutations in MKKS in Group II patients was 24%, i.e., six times higher than the
published rate for unselected BBS patients, suggesting that small-scale linkage
analyses may be useful in suitable families. McKusick-Kaufman syndrome (MKS) is an autosomal recessive disorder characterized
by post-axial polydactyly, congenital heart defects and hydrometrocolpos, a
congenital structural abnormality of female genitalia. Mutations in the MKKS
gene have also been shown to cause some cases of Bardet-Biedl syndrome (BBS)
which is characterized by obesity, pigmentary retinopathy, polydactyly, renal
abnormalities and hypogenitalism with secondary features of hypertension and
diabetes. Although there is overlap in clinical features between MKS and BBS,
MKS patients are not obese and do not develop retinopathy or have learning
disabilities. To further explore the pathophysiology of BBS and the related
disorder MKS, we have developed an Mkks(-/-) mouse model. This model shows that
the absence of Mkks leads to retinal degeneration through apoptosis, failure of
spermatozoa flagella formation, elevated blood pressure and obesity. The obesity
is associated with hyperphagia and decreased activity. In addition, neurological
screening reveals deficits in olfaction and social domice. The mice do not
have polydactyly or vaginal abnormalities. The phenotype of the Mkks(-/-) mice
closely resembles the phenotype of other mouse models of BBS (Bbs2(-/-) and
Bbs4(-/-)). These observations suggest that the complete absence of MKKS leads
to BBS while the MKS phenotype is likely to be due to specific mutations. McKusick-Kaufman syndrome is a rare, autosomal, recessive disorder characterized
by hydrometrocolpos, post-axial polydactyly, and congenital heart disease. Less
than one hundred cases have been reported in the English literature to date,
mainly in the Amish population; sporadic cases have also been described. We
present a case of an Arab Bedouin girl who presented with features resembling
this syndrome. McKusick-Kaufman syndrome (MKS, OMIM #236700) is a rare syndrome inherited in an
autosomal recessive pattern with a phenotypic triad comprising hydrometrocolpos
(HMC), postaxial polydactyly (PAP), and congenital cardiac disease (CHD). The
syndrome is caused by mutations in the MKKS gene mapped onto chromosome 20p12
between D20S162 and D20S894 markers. Mutations in the same gene causes
Bardet-Biedl-6 syndrome (BBS-6, OMIM #209900) inherited in an autosomal
recessive pattern. BBS-6 comprises retinitis pigmentosa, polydactyly, obesity,
mental retardation, renal and genital anomalies. HMC, CHD, and PAP defects can
also occur in BBS-6, and there is a significant clinical overlap between MKS and
BBS-6 in childhood. We describe a new borderline case of MKS and BBS syndrome
and suggest insights for understanding correlation between MKKS gene mutations
and clinical phenotype. Here, we report the results of molecular analysis of
MKKS in a female proband born in an Italian nonconsanguineous healthy family
that presents HMC and PAP. The mutational screening revealed the presence of two
different heterozygous missense variants (p.242A>S in exon 3, p.339 I>V in exon
4) in the MKKS gene, and a nucleotide variation in 5'UTR region in exon 2 (-417
A>C). McKusick-Kaufman syndrome is a rare autosomal recessive disease diagnosed by
polydactyly, hydrometrocolpos, and congenital heart disease. We present an
unusual laparotomy confirmed urogenital MRI finding (atretic vaginal pouch) in a
3-month-old girl with McKusick-Kaufman syndrome. Up to our knowledge, this MR
finding has not been reported in the literature yet. Neonatal hydrometrocolpos (HMC) is a rare Mullerian duct anomaly with an
incidence of 0.006%. It occurs due to blockage of the vagina with accumulation
of mucus secretions proximal to the obstacle. These secretions are secondary to
intrauterine and postnatal stimulation of uterine and cervical glands by
maternal estrogens. A triad of congenital HMC, polydactyly, and cardiac
anomalies are the cardinal features of McKusick-Kaufman syndrome, which is also
known as hydrometrocolpos-polydactyly syndrome. Bardet-Biedl syndrome is a
well-known combination of hypogonadism, obesity, postaxial polydactyly, renal
dysplasia, retinal degeneration, and mental impairment. In this case report, we
describe a neonate with HMC, polydactyly, and hydronephrosis. |
Is Ixodes a species of tick? | Ixodes is a family of hard ticks. | From September 1997 through July 1999, 300 individuals and 46 species of birds
were mist-netted and screened for ticks and spirochetes on St. Catherine's
Island, Liberty County, GA. Seventy-six (25%) of the birds were parasitized by a
meal intensity of 4.6 ticks. Seasonally, more birds were infested with ticks
during the summer (50% in 1998, 34% in 1999) than in spring (15% in 1998, 11% in
1999) or fall (21% in 1997, 20% in 1998), mainly because of severe infestations
on some birds by immature stages of the lone star tick, Amblyomma americanum
(L.), during this season. Eight species ofticks were recovered from 14 species
of birds during this study: A. americanum (74 nymphs, 168 larvae); the
blacklegged tick, Ixodes scapularis Say (11 nymphs, 28 larvae), the Gulf Coast
tick, Amblyomma maculatum Koch (two nymphs, 29 larvae); Ixodes minor Neumann (16
larvae); the rabbit tick. Haemaphysalis leporispalustris (Packard) (one nymph,
14 larvae); the bird tick Ixodes brunneus Koch (two larvae); the American dog
tick, Dermacentor variabilis (Say) (one nymph); and Ixodes affinis Neumann (one
larva). The Carolina wren was parasitized by more species of ticks (seven) than
any other bird species, followed by the northern cardinal (five), white-throated
sparrow (four) and painted bunting (three). Spirochetes were isolated in BSK II
medium from one tick (a nymphal A. americanum) and from skin biopsies of 12 (4%)
of the individual birds (three downy woodpeckers, three northern waterthrushes,
two Carolina wrens, one American redstart, one pine warbler, one Swainson's
thrush, and one white-eyed vireo) all in fall 1997. This concentrated phenology
of spirochete isolations might reflect periodic amplification or recrudescence
of spirochetes in reservoir avian hosts. The Ixodes ricinus species complex is a group of ticks distributed in almost all
geographic regions of the world. Lyme borreliosis spirochetes are primarily
transmitted by tick species within this complex. It has been hypothesized that
the Lyme vector ticks around the world are closely related and represent a
monophyletic group. This implies that vector competence in ixodid ticks for Lyme
agents might have evolved only once. To test this hypothesis, we used a
molecular phylogenetic approach. Two fragments of mitochondrial 16S ribosomal
deoxyribonucleic acid were sequenced from 11 species in the I. ricinus complex
and from 16 other species of Ixodes. Phylogenetic analysis using Bayesian
methodology indicated that the I. ricinus complex is not a monophyletic group
unless 3 additional Ixodes species are included in it. The known major vectors
of Lyme disease agents in different areas of the world are not sister taxa. This
suggests that acquisition of the ability to transmit borreliosis agents in
species of Ixodes may have multiple origins. Lyme borreliosis, or Lyme disease (LD), is a tick-borne zoonotic infection of
biomedical significance, caused by Borrelia burgdorferi sensu lato (s.l.)
spirochetes and transmitted by Ixodes species ticks. It usually circulates among
wildlife vertebrate reservoirs and vector ticks but may infect humans, causing
multisystem problems. In far western and northern North America, the host
reservoirs, tick vectors, and genospecies of Borrelia are well known but not so
in the southern U.S., where there is controversy as to the presence of "true"
LD. Here we report the presence of the LD spirochete B. burgdorferi sensu
stricto (s.s.) and Borrelia bissettii, three main reservoir hosts, and two
enzootic tick vectors in the southeastern U.S. The two enzootic tick vectors,
Ixodes affinis and Ixodes minor, rarely bite humans but are more important than
the human biting "bridge" vector, Ixodes scapularis, in maintaining the enzootic
spirochete cycle in nature. We also report extraordinary longevities and
infections in the reservoir rodents Peromyscus gossypinus, Sigmodon hispidus,
and Neotoma floridana. The world's argasid tick fauna comprises 183 species in four genera, namely
Argas, Carios, Ornithodoros and Otobius in the family Argasidae. The ixodid tick
fauna consists of 241 species in the genus Ixodes and 442 species in the genera
Amblyomma, Anomalohimalaya, Bothriocroton, Cosmiomma, Dermacentor,
Haemaphysalis, Hyalomma, Margaropus, Nosomma, Rhipicentor and Rhipicephalus in
the family Ixodidae, with the genus Boophilus becoming a subgenus of the genus
Rhipicephalus. The family Nuttalliellidae is represented by the monospecific
genus Nuttalliella. The species names of these ticks, based on seven previous
complete or partial listings, as well as those of recently described new
species, are presented in tabular format. During a 3-yr comprehensive study, 196 ixodid ticks (9 species) were collected
from 89 passerine birds (32 species) from 25 localities across Canada to
determine the distribution of avian-associated tick species and endogenous Lyme
disease spirochetes, Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt,
and Brenner. We report the following first records of tick parasitism on avian
hosts: the rabbit-associated tick, Ixodes dentatus Marx, from Manitoba and
Ontario; the mouse tick, Ixodes muris Bishopp and Smith, from British Columbia;
and the blacklegged tick, Ixodes scapularis Say, from New Brunswick. Moreover,
we provide the first record of the Neotropical tick, Amblyomma humerale Koch (1
nymph), in Canada and its parasitism of any bird. This tick was compared
morphologically with nymphs of other Neotropical Amblyomma spp., and
genetically, using a 344-bp fragment of the 12S rDNA sequence of 41 New World
Amblyomma species. The first collections of the western blacklegged tick, Ixodes
pacificus Cooley and Kohls, from passerine species in Alberta and British
Columbia, are also reported. Notably, we further report the first isolation of
B. burgdorferi from the bird tick, Ixodes auritulus Neumann, collected from an
American robin, Turdus migratorius L., on Vancouver Island. Furthermore, B.
burgdorferi-positive I. auritulus larvae were collected from a
reservoir-competent fox sparrow, Passerella iliaca (Merrem). Our findings
indicate that ground-dwelling passerines, in particular, are parasitized by
certain ixodid ticks and play an important role across Canada in the wide
dispersal of B. burgdorferi-infected ticks and increased risk of Lyme disease
exposure. The genetic identity of Ixodes granulatus ticks was determined for the first
time in Taiwan. The phylogenetic relationships were analyzed by comparing the
sequences of mitochondrial 16S ribosomal DNA gene obtained from 19 strains of
ticks representing seven species of Ixodes and two outgroup species
(Rhipicephalus sanguineus and Haemaphysalis inermis). Four major clades could be
easily distinguished by neighbour-joining analysis and were congruent by
maximum-parsimony method. All these I. granulatus ticks of Taiwan were
genetically affiliated to a monophyletic group with highly homogeneous sequences
(92.2-99.3% similarity), and can be discriminated from other Ixodes species and
other genera of ticks with a sequence divergence ranging from 11.7 to 30.8%.
Moreover, intraspecific analysis revealed that two distinct lineages are evident
between the same species of I. granulatus ticks collected from Taiwan and
Malaysia. Our results demonstrate that all these I. granulatus ticks of Taiwan
represent a unique lineage distinct from the common vector ticks (I. ricinus
complex) for Borrelia burgdorferi spirochetes. Among the various species of hard ticks, Ixodes ricinus is the most frequently
found tick throughout Europe. As with other ixodid ticks, the developmental
cycle runs through three stages. In each stage a blood meal is required in order
to develop to the next stage. Ixodes ricinus has been found to feed on more than
300 different vertebrate species. Usually, larval ticks feed on small mammals
such as mice and become infected with various microorganisms and viruses, of
which some are substantial pathogens to humans. The pathogens remain in the tick
during molting and are thus transstadially transmitted to the next developmental
stage. Pathogens transmitted to humans are the agents of Lyme borreliosis, the
tick-borne encephalitis virus, Rickettsia species, Anaplasma phagocytophilum,
occasionally Francisella tularensis, and protozoal Babesia species. Within the
scope of an EU project Ixodes ricinus ticks from all federal states of Austria
were searched by means of PCR methods for bacterial pathogens such as Anaplasma
phagocytophilum, Borrelia burgdorferi sensu lato, Coxiella burnetii, Ehrlichia
spp., Francisella tularensis, Rickettsia spp., and protozoal Babesia.
Additionally, the prevalence of Bartonella spp. in this tick species was also
determined. Besides the singular detection of Coxiella burnetii and Francisella
tularensis in one tick collection site the overall prevalence of Anaplasma
phagocytophilum, borreliae, rickettsae and babesiae in Ixodes ricinus amounted
to 15%, 14%, 6% and surprising 36% and 51%, respectively. Bartonellae were
detected in about 7%. This paper presents results of an investigation and listing of tick species
found in China during a survey in all 28 provinces. This will be a step towards
a definitive list of tick species and their distribution. To date, the tick
fauna of this area consists of 117 species in the following families:
Argasidae-Argas (7 species), Carios (4 species) and Ornithodoros (2 species);
Ixodidae-Amblyomma (8 species), Anomalohimalaya (2 species), Dermacentor (12
species), Haemaphysalis (44 species), Hyalomma (6 species), Ixodes (24 species)
and Rhipicephalus (8 species). Some well known ticks carrying and transmitting
many infectious agents to man and domestic animals are also found in China.
These include Ixodes persulcatus, Haemaphysalis longicornis, Rhipicephalus
sanguineus, R. (Boophilus) microplus and Hyalomma asiaticum. It is worth
mentioning that Ixodes rangtangensis Teng and Haemaphysalis xinjiangensis Teng
should be relegated to a synonym of I. moschiferi and Hae. danieli,
respectively. The distribution of ticks over the provinces of China is also
discussed. The information on ticks in some areas such as He is not
exhaustive. Understanding epidemiology of the tick-borne pathogens requires the accurate
identification of the vector ticks. Morphological analysis of ticks is difficult
and often leads to misidentification. Molecular techniques offer an alternative
approach of tick identification. To date, no practical and reliable molecular
assays for discrimination of Euro-Asian ticks are available. Our aim was to
develop such an assay for discrimination between four Euro-Asian tick species of
high medical importance such as Ixodes ricinus, Ixodes persulcatus, Ixodes
hexagonus, and Dermacentor reticulatus. As a basis, we have chosen conventional
species-specific polymerase chain reaction (PCR), a technique providing a good
combination of simplicity and reliability. The DNA information available on
ticks was searched for orthologous loci containing stretches of sequence
dissimilarity sufficient for designing species-specific primers. ITS2 locus
(second internal transcribed region of the rRNA gene cluster) was found to be
the most favorable for primer design. Finally, for each of the three Ixodes
species a PCR was developed amplifying only for the targeted species. One PCR
amplified the entire ITS2 locus of the four species and allowed discrimination
of D. reticulatus from the Ixodes species on the basis of the size difference of
the respective PCR products. This PCR system was successfully tested for
discrimination of the ticks at different maturation stages (larva, nymph, and
adult) in engorged and unfed conditions, and therefore it may be useful for
large-scale epidemiological studies. Differentiation between the closely related
I. ricinus and I. persulcatus, the two species most often occurring in the
tick-borne diseases in Eurasia, is of special importance. To investigate the genetic specificity of Ixodes granulatus ticks collected from
Taiwan, the genetic identities and phylogenetic relationships were analyzed by
comparing the sequences of the internal transcribed spacer 2 (ITS2) region
obtained from 27 strains of ticks representing twelve species of Ixodes. Five
major clades can be easily distinguished by neighbour-joining analysis and were
congruent by maximum-parsimony method. All these I. granulatus ticks collected
from Taiwan and Japan were genetically affiliated to a monophyletic group with
highly homogeneous sequences (95.8-99.5% similarity), and can be discriminated
from other species and subgenera of Ixodes ticks with a sequence divergence
ranging from 13.6% to 62.9%. Moreover, interspecific analysis revealed that four
distinct lineages are evident between Ixodes ticks, and all these I. granulatus
ticks collected from Taiwan and Japan belong to the same lineage. Our results
provide the first investigation on the genetic specificity of I. granulatus
ticks, and demonstrate that all these I. granulatus ticks represent a unique
lineage distinct from other species and subgenera of Ixodes ticks. The
feasibility of ITS2-based genetic analysis for species-specific identification
of I. granulatus ticks around East Asia was highly anticipated. Ixodes species ticks are competent vectors of tick-borne viruses including
tick-borne encephalitis and Powassan encephalitis. Tick saliva has been shown to
facilitate and enhance viral infection. This likely occurs by saliva-mediated
modulation of host responses into patterns favorable for viral infection and
dissemination. Because of the rapid kinetics of tick-borne viral transmission,
this modulation must occur as early as tick attachment and initiation of
feeding. In this study, cutaneous bite-site lesions were analyzed using
Affymetrix mouse genome 430A 2.0 arrays and histopathology at 1, 3, 6, and 12
hours after uninfected Ixodes scapularis nymphal tick attachment. At 1 and 3 hrs
after attachment, the gene expression profile is markedly different than at
later time points. Upregulated gene ontology term clusters enriched at 1 and 3
hrs were related to post-translational modification. At 6 and 12 hrs,
cytoskeletal rearrangements, DNA replication/cell division, inflammation, and
chemotaxis were prominent clusters. At 6 and 12 hrs, extracellular matrix,
signaling, and DNA binding clusters were downregulated. Histopathological
analysis shows minimal inflammation at 1 and 3 hrs but an appreciable neutrophil
infiltrate at 6 and 12 hrs. In addition, putative hyperemia, localized necrosis,
and increased ECM deposition were identified. Putting the gene expression and
histopathology analysis together suggests early tick feeding is characterized by
modulation of host responses in resident cells that merges into a nascent,
neutrophil-driven immune response by 12 hrs post-attachment. Microtus californicus scirpensis is an endangered, isolated subspecies of
California vole. It requires water pools and riparian bulrush (Schoenoplectus
americanus) and occupies some of the rarest habitat of any North American
mammal. The minimally vegetated, extremely arid desert surrounding the pools is
essentially uninhabitable for Ixodes species ticks. We describe an enzootic
cycle of Borrelia carolinensis in Ixodes minor ticks at a site 3500 km distant
from the region in which I. minor is known to occur in Tecopa Host Springs, Inyo
County, eastern Mojave Desert, California. Voles were live-trapped, and ticks
and blood samples queried by PCR and DNA sequencing for identification and
determination of the presence of Borrelia spp. Between 2011-2013, we found 21
Ixodes minor ticks (prevalence 4-8%) on Amargosa voles and Reithrodontomys
megalotis. DNA sequencing of 16S rRNA from ticks yielded 99% identity to
I. minor. There was 92% identity with I. minor in the calreticulin gene
fragment. Three ticks (23.1%), 15 (24%) voles, three (27%) house mice, and one
(7%) harvest mice were PCR positive for Borrelia spp. Sequencing of the 5S-23S
intergenic spacer region and flagellin gene assigned Amargosa vole Borrelia
strains to B. carolinensis. Ixodes minor, first described in 1902 from a single
Guatemalan record, reportedly occurs only in the southeast American on small
mammals and birds. The source of this tick in the Mojave Desert and time scale
for introduction is not known but likely via migratory birds. Borrelia strains
in the Amargosa ecosystem most closely resemble B. carolinensis. B. carolinensis
occurs in a rodent-I. minor enzootic cycle in the southeast U.S. although its
epidemiological significance for people or rodents is unknown. The presence of a
tick and Borrelia spp. only known from southeast U.S. in this extremely isolated
habitat on the other side of the continent is of serious concern because it
suggests that the animals in the ecosystem could be vulnerable to further
incursions of pathogens and parasites. Seventy species of ticks are known from Australia: 14 soft ticks (family
Argasidae) and 56 hard ticks (family Ixodidae). Sixteen of the 70 ticks in
Australia may feed on humans and domestic animals (Barker and Walker 2014). The
other 54 species of ticks in Australia feed only on wild mammals, reptiles and
birds. At least 12 of the species of ticks in Australian also occur in Papua New
Guinea. We use an image-matching system much like the image-matching systems of
field guides to birds and flowers to identify Ixodes holocyclus (paralysis
tick), Ixodes cornuatus (southern paralysis tick) and Rhipicephalus (Boophilus)
australis (Australian cattle tick). Our species accounts have reviews of the
literature on I. holocyclus (paralysis tick) from the first paper on the biology
of an Australian tick by Bancroft (1884), on paralysis of dogs by I. holocyclus,
to papers published recently, and of I. cornuatus (southern paralysis tick) and
Rhipicephalus (Boophilus) australis (Australian cattle tick). We comment on four
controversial questions in the evolutionary biology of ticks: (i) were
labyrinthodont amphibians in Australia in the Devonian the first hosts of soft,
hard and nuttalliellid ticks?; (ii) are the nuttalliellid ticks the sister-group
to the hard ticks or the soft ticks?; (iii) is Nuttalliella namaqua the missing
link between the soft and hard ticks?; and (iv) the evidence for a lineage of
large bodied parasitiform mites (ticks plus the holothyrid mites plus the
opiliocarid mites). Borrelia miyamotoi is a newly described emerging pathogen transmitted to people
by Ixodes species ticks and found in temperate regions of North America, Europe,
and Asia. There is limited understanding of large scale entomological risk
patterns of B. miyamotoi and of Borreila burgdorferi sensu stricto (ss), the
agent of Lyme disease, in western North America. In this study, B. miyamotoi, a
relapsing fever spirochete, was detected in adult (n=70) and nymphal (n=36)
Ixodes pacificus ticks collected from 24 of 48 California counties that were
surveyed over a 13 year period. Statewide prevalence of B. burgdorferi sensu
lato (sl), which includes B. burgdorferi ss, and B. miyamotoi were similar in
adult I. pacificus (0.6% and 0.8%, respectively). In contrast, the prevalence of
B. burgdorferi sl was almost 2.5 times higher than B. miyamotoi in nymphal I.
pacificus (3.2% versus 1.4%). These results suggest similar risk of exposure to
B. burgdorferi sl and B. miyamotoi from adult I. pacificus tick bites in
California, but a higher risk of contracting B. burgdorferi sl than B. miyamotoi
from nymphal tick bites. While regional risk of exposure to these two
spirochetes varies, the highest risk for both species is found in north and
central coastal California and the Sierra Nevada foothill region, and the lowest
risk is in southern California; nevertheless, tick-bite avoidance measures
should be implemented in all regions of California. This is the first study to
comprehensively evaluate entomologic risk for B. miyamotoi and B. burgdorferi
for both adult and nymphal I. pacificus, an important human biting tick in
western North America. Ixodes holocyclus (Acarina: Ixodidae) and Ixodes cornuatus (Acarina: Ixodidae)
are two tick species found in the more densely populated areas of Australia and
are known to be the cause of the neurotoxic disease tick paralysis in humans and
mammals. Borreliosis otherwise known as Lyme disease is an emerging infectious
disease in humans in Australia. Borrelia burgdorferi sensu stricto
(Spirochaetales: Spirochaetaceae) and sensu lato are closely related spirochetal
species that are the causative agents of Lyme disease in humans. Clinical
transmission of this tick-borne disease can be identified in several but not all
cases by a characteristic rash known as erythema migrans. However, there has
been no study of the tick vectors of this infection in Australia. We used
morphological and molecular techniques to identify unequivocally the ticks on
the patients of this study to be I. holocyclus and then show the presence of B.
burgdorferi sensu stricto infection in erythema migrans biopsies. I. holocyclus
has not previously been associated with erythema migrans or Lyme disease. Two
patients presented to the lead author's medical practice with erythema migrans
in mid and late 2012. The morphology and cytochrome oxidase 1 and ITS2 genes of
the two ticks were studied. The skin at the attachment site was sampled by
central biopsy for both real time and endpoint Borrelia polymerase chain
reaction (PCR) analysis and subsequent sequencing. Morphologically, the two
ticks were either I. holocyclus or I. cornuatus. Molecular studies and
nucleotide sequencing revealed that both ticks were I. holocyclus. Real time and
endpoint PCR on the central tissue biopsy samples returned positive results for
B. burgdorferi DNA. Our results are evidence for transmission of B. burgdorferi
sensu stricto species to humans by the tick I. holocyclus in Australia. I.
holocyclus is commonly associated with human tick bites on virtually the entire
eastern coastline of Australia. Four members of the Ixodes ricinus species complex, Ixodes pacificus, Ixodes
persulcatus, Ixodes ricinus and Ixodes scapularis, have, between them, a
worldwide distribution within the northern hemisphere. They are responsible for
the transmission of several animal and human pathogens, including the causal
agents of Lyme borreliosis, tick-borne encephalitis, human granulocytic
anaplasmosis and human babesiosis. Despite the importance of these ticks as
vectors, the knowledge and understanding of the role that diapause plays in
their complex life cycles are confused and incomplete. In view of the continuing
geographic spread of these tick species, as well as the effects of climate
change on vector-borne diseases, it is timely to encourage research on diapause
phenomena to improve understanding of their biology and of pathogen transmission
dynamics. In our review we seek to clarify thinking on the topic and to address
gaps in our knowledge that require the attention of researchers. BACKGROUND: In a recent study on ixodid bat ticks from Eurasia, a high genetic
difference was found between Ixodes vespertilionis from Europe and Vietnam.
Accordingly, it was proposed that I. vespertilionis is a species complex, with
at least one additional, hitherto undescribed species. The aim of the present
study was to investigate the morphology of bat ticks from Vietnam and to assess
their taxonomic status in comparison with those collected in Europe.
FINDINGS: Ixodid bat ticks (two females and two nymphs) collected from the
pomona leaf-nosed bat (Hipposideros pomona) (Hipposideridae) and intermediate
horseshoe bat (Rhinolophus affinis) (Rhinolophidae) in Vietnam showed major
morphological differences from European isolates of I. vespertilionis, including
the shape of the scutum, the enclosure and shape of porose areas, the presence
of a caudo-lateral collar-like ridge ventrally on the basis capituli, polytrich
coxae with short setae, and grouped (non-linear) arrangement of anterior pit
sensillae in Haller's organ.
CONCLUSIONS: In this study the female and the nymph of an ixodid bat tick
species from Vietnam are described for the first time. The genetic and
morphological differences between I. vespertilionis Koch, 1844 and these bat
ticks from Vietnam justify the status of the latter as a distinct species,
Ixodes collaris Hornok n. sp. Ixodes ariadnae is a tick species of bats so far reported only in Central
Europe, with its description based on the female and nymph. This study describes
the male and larva in order to complete the description of the species. Male
ticks collected from cave walls in Hungary showed a different morphology from
those of I. vespertilionis and I. simplex. Molecular analysis of the cytochrome
oxidase subunit I (COI) gene of these ticks verified them as conspecific to I.
ariadnae. In addition, a larva of I. ariadnae was removed from a Daubenton's bat
(Myotis daubentonii Kuhl, 1817). The male of I. ariadnae is characterized by
long legs (7-8mm; I. vespertilionis: 8-10mm; I. simplex: 2-2.2mm), relatively
short palpal setae (30-100μm; I. vespertilionis: 100-200μm; I. simplex: 20-50μm)
and straight lateral edge of palps, the genital aperture (enclosed by a line of
sclerotization) situated anteriorly to second intercoxal space and rounded
coxae. The larva of I. ariadnae has long legs (2-2.2mm; I. vespertilionis:
1.6-1.8mm; I. simplex: 1mm), broad palps (length×width: 200×90μm; I.
vespertilionis: 200×70μm; I. simplex: 140×60μm), pentagonal and posteriorly
reverse bell-shaped scutum. These features allow to distinguish the male and the
larva of I. ariadnae from those of I. vespertilionis (of which the male has
longer palpal setae and curved lateral edge of palps, the genital aperture is
situated posterior to the second intercoxal space, and the second coxae are
squared; the larva of I. vespertilionis has narrower palps and posteriorly
triangular scutum) and I. simplex (of which the male and the larva have
considerably shorter legs, palps). BACKGROUND: With the resurgence of tick-borne diseases such as Lyme disease and
the emergence of new tick-borne pathogens such as Powassan virus, understanding
what distinguishes vectors from non-vectors, and predicting undiscovered tick
vectors is a crucial step towards mitigating disease risk in humans. We aimed to
identify intrinsic traits that predict which Ixodes tick species are confirmed
or strongly suspected to be vectors of zoonotic pathogens.
METHODS: We focused on the well-studied tick genus Ixodes from which many
species are known to transmit zoonotic diseases to humans. We apply generalized
boosted regression to interrogate over 90 features for over 240 species of
Ixodes ticks to learn what intrinsic features distinguish zoonotic vectors from
non-vector species. In addition to better understanding the biological
underpinnings of tick vectorial capacity, the model generates a per species
probability of being a zoonotic vector on the basis of intrinsic biological
similarity with known Ixodes vector species.
RESULTS: Our model predicted vector status with over 91% accuracy, and
identified 14 Ixodes species with high probabilities (80%) of transmitting
infections from animal hosts to humans on the basis of their traits.
Distinguishing characteristics of zoonotic tick vectors of Ixodes tick species
include several anatomical structures that influence host seeking behavior and
blood-feeding efficiency from a greater diversity of host species compared to
non-vectors.
CONCLUSIONS: Overall, these results suggest that zoonotic tick vectors are most
likely to be those species where adult females hold a fecundity advantage by
producing more eggs per clutch, which develop into larvae that feed on a greater
diversity of host species compared to non-vector species. These larvae develop
into nymphs whose anatomy are well suited for more efficient and longer feeding
times on soft-bodied hosts compared to non-vectors, leading to larger adult
females with greater fecundity. In addition to identifying novel, testable
hypotheses about intrinsic features driving vectorial capacity across Ixodes
tick species, our model identifies particular Ixodes species with the highest
probability of carrying zoonotic diseases, offering specific targets for
increased zoonotic investigation and surveillance. Tick-induced mammalian meat allergy has become an emergent allergy world-wide
after van Nunen et al. first described the association between tick bites and
the development of mammalian meat allergy in 2007. Cases of mammalian meat
allergy have now been reported on all 6 continents where humans are bitten by
ticks, in 17 countries - Australia, United States of America (USA), Europe
(France, Spain, Germany, Belgium, Switzerland, Sweden, United Kingdom, Italy,
and Norway), Asia (Korea and Japan), Central America (Panama), South America
(Brazil), and Africa (South Africa and Ivory Coast). To date, in each of these
countries, bites from only a single tick species have been linked to the
development of mammalian meat allergy: Ixodes holocyclus (Australia), Amblyomma
americanum (USA), Ixodes ricinus (Europe), and Ixodes cajennense (Panama) are
confirmed as culprits, and Ixodes nipponensis (Japan and Korea), Amblyomma
sculptum (Brazil), Amblyomma variegatum (Ivory Coast), and Haemaphysalis
longicornis (Japan) suspected of provoking mammalian meat allergy after tick
bite. Other tick species remain to be formally identified (South Africa).
Identification of tick species associated with development of mammalian meat
allergy is crucial to the uptake of public health measures to prevent tick bites
from culprit tick species, for both individuals living in these tick-endemic
areas and those who choose to visit these regions. We report a tick associated
with the enhancement of mammalian meat anaphylaxis after tick bite which is
novel for both Australia and the world and establishes Ixodes (Endopalpiger)
australiensis as a second tick species associated with mammalian meat allergy in
Australia. From July 2006 through August 2017, a passive surveillance study of Ixodes ticks
submitted from California, Oregon, and Washington was conducted by the
TickReport program at the University of Massachusetts, Amherst. In total, 549
human-biting Ixodes ticks were submitted comprising both endemic and nonendemic
species. We found that 430 endemic ticks were from 3 Ixodes species: Ixodes
pacificus, Ixodes spinipalpis, and Ixodes angustus, whereas Ixodes scapularis
(n = 111) was the most common species among the 119 nonendemic ticks. The
submission peak for nymphal I. pacificus and I. spinipalpis was June, while
submission peak for adult I. pacificus and nymphal I. angustus was April and
September, respectively. Endemic ticks commonly attached to the lower
extremities of their victims, and individuals younger than 9 years old were
frequently bitten. The infection prevalence of Borrelia burgdorferi sensu lato,
Borrelia miyamotoi, and Anaplasma phagocytophilum in I. pacificus ticks was
1.31%, 1.05%, and 0.52%, respectively, and the prevalence of B. burgdorferi s.
l. and A. phagocytophilum in I. spinipalpis ticks was 14.29% and 10.71%,
respectively. Furthermore, two species within the B. burgdorferi s. l. complex
were detected in West Coast ticks: B. burgdorferi sensu stricto and Borrelia
lanei. I. spinipalpis had the highest Borrelia prevalence among endemic ticks,
and it was caused exclusively by B. lanei. Borrelia mayonii, Babesia microti,
and Ehrlichia muris-like agent were not detected in these endemic ticks. In this
study, we show that many nonendemic Ixodes ticks (119/549) are most likely
acquired from travel to a different geographic region. We report cases of
conventionally recognized nonhuman feeders (I. spinipalpis and I. angustus)
parasitizing humans. The highest pathogen prevalence in I. spinipalpis may
indicate a larger public health threat than previously thought, and the enzootic
life cycle and pathogenicity of B. lanei warrant further study. In 2014, a new tick species, Ixodes inopinatus, was described, which is closely
related to Ixodes ricinus. So far, I. inopinatus has been found in Tunisia,
Morocco, Spain, Portugal, Romania, Austria, and southern Germany. No data is yet
available regarding occurrence of I. inopinatus in northern Germany and the
potential role of I. inopinatus as a vector for tick-borne pathogens. Therefore,
3845 DNA samples from Ixodes ticks collected for prevalence studies on Borrelia
spp., Rickettsia spp., and Anaplasma phagocytophilum during the years 2010-2015
in the northern German cities of Hamburg and Hanover were differentiated into I.
ricinus or I. inopinatus by sequencing a part of the 16S rRNA gene. In total, 4%
(137/3845) of the sequenced ticks were assigned to the species I. inopinatus and
96% (3708/3845) to I. ricinus. The prevalence of Borrelia spp., Rickettsia spp.,
and A. phagocytophilum DNA in I. inopinatus was 34% (46/137), 46% (63/137), and
3% (4/137), respectively, whereas the prevalence of these bacteria in I. ricinus
was 25% (919/3708), 47% (1729/3708), and 4% (135/3708), respectively. Compared
with I. ricinus, significantly more I. inopinatus ticks tested positive for
Borrelia. To the best of our knowledge, this is the first report of I.
inopinatus in northern Germany. Detection of the DNA of Borrelia spp.,
Rickettsia spp., and A. phagocytophilum in questing I. inopinatus indicates a
potential role of this tick species as a vector of these pathogens, which needs
to be confirmed by transmission experiments. BACKGROUND: Babesiosis is a parasitic vector-borne disease of increasing public
health importance. Since the first human case was reported in 1957, zoonotic
species have been reported on nearly every continent. Zoonotic Babesia is
vectored by Ixodes ticks and is commonly transmitted in North America by Ixodes
scapularis, the tick species responsible for transmitting the pathogens that
also cause Lyme disease, Powassan virus, and anaplasmosis in humans. Predicted
climate change is expected to impact the spread of vectors, which is likely to
affect the distribution of vector-borne diseases including human babesiosis.
METHODS: A scoping review has been executed to characterize the global evidence
on zoonotic babesiosis. Articles were compiled through a comprehensive search of
relevant bibliographic databases and targeted government websites. Two reviewers
screened titles and abstracts for relevance and characterized full-text articles
using a relevance screening and data characterization tool developed a priori.
RESULTS: This review included 1394 articles relevant to human babesiosis and/or
zoonotic Babesia species. The main zoonotic species were B. microti, B.
divergens, B. duncani and B. venatorum. Articles described a variety of study
designs used to study babesiosis in humans and/or zoonotic Babesia species in
vectors, animal hosts, and in vitro cell cultures. Topics of study included:
pathogenesis (680 articles), epidemiology (480), parasite characterization
(243), diagnostic test accuracy (98), mitigation (94), treatment (65),
transmission (54), surveillance (29), economic analysis (7), and societal
knowledge (1). No articles reported predictive models investigating the impact
of climate change on Babesia species.
CONCLUSION: Knowledge gaps in the current evidence include research on the
economic burden associated with babesiosis, societal knowledge studies,
surveillance of Babesia species in vectors and animal hosts, and predictive
models on the impact of climate change. The scoping review results describe the
current knowledge and knowledge gaps on zoonotic Babesia which can be used to
inform future policy and decision making. Author information:
(1)Laboratório Especial de Coleções Zoológicas, Instituto Butantan, São Paulo,
SP, Brazil; Mestrado em Medicina e Bem-Estar Animal, Universidade Santo Amaro,
São Paulo, SP, Brazil.
(2)Instituto Nacional de Tecnología Agropecuaria, Estación Experimental
Agropecuaria Rafaela, Consejo Nacional de Investigaciones Científicas y
Técnicas, Rafaela, Santa Fe, Argentina.
(3)Departamento de Patologia Veterinária, Faculdade de Ciências Agrárias e
Veterinárias, Universidade Estadual Paulista - UNESP, Jaboticabal, SP, Brazil.
(4)Laboratório de Zoologia, Departamento de Biologia, Instituto de Ciências
Biológicas, Universidade Federal do Amazonas, Manaus, AM, Brazil.
(5)Mestrado em Medicina e Bem-Estar Animal, Universidade Santo Amaro, São Paulo,
SP, Brazil.
(6)Departamento de Engenharia de Pesca e Ciências Biológicas, Universidade do
Estado de Santa Catarina, Lages, SC, Brazil; Laboratório de Zoologia e
Parasitologia, Universidade do Planalto Catarinense, Lages, SC, Brazil.
(7)Laboratório de Identificação e Pesquisa de Fauna Sitrópica da Prefeitura
Municipal de São Paulo, São Paulo, SP, Brazil.
(8)Departamento de Medicina Veterinária Preventiva e Saúde animal, Faculdade de
Medicina Veterinária e Zootecnia, Universidade de São Paulo, Av. Prof. Orlando
Marques de Paiva 87, Cidade Universitária, 05508-270, São Paulo, SP, Brazil.
Electronic address: [email protected]. The expanding geographic ranges of tick species that are known pathogen vectors
can have implications for human, domestic animal, and wildlife health. Although
Alaska is home to several hard tick species, it has historically been outside of
the range of the most common medically important ticks in the contiguous United
States and western Canada. To assess the status of tick species establishment in
the state and to provide a baseline for tracking future change in the
distribution of ticks, we reviewed and compiled historical tick records and
summarized recent tick occurrence records collected through the development of
the Alaska Submit-A-Tick Program and through tick drag sampling at sentinel
sites in southcentral Alaska. Between 1909-2019, there were 1190 tick records
representing 4588 individual ticks across 15 species in Alaska. The majority of
ticks were species historically found in Alaska: Haemaphysalis leporispalustris,
Ixodes angustus, Ixodes auritulus, Ixodes howelli, Ixodes signatus, and Ixodes
uriae. Over half of all tick records in the state were collected in the last
10 yr. During this time, the number of tick records and the number of tick
species recorded in Alaska each year has increased substantially. Between
2010-2019, there were 611 tick records representing 1921 individual ticks. The
most common hosts for reported ticks were domestic animals (n = 343, 56 %)
followed by small wild mammals (n = 147, 24 %), humans (n = 49, 8%), and wild
birds (n = 31, 5%). Less than 5% of records (n = 25) were of unattached ticks
found in the environment. Since 2007, non-native tick species have been
documented in the state every year, including Amblyomma americanum, Dermacentor
andersoni, Dermacentor occidentalis, Dermacentor variabilis, Ixodes pacificus,
Ixodes ricinus, Ixodes scapularis, Ixodes texanus, and Rhipicephalus sanguineus
sensu lato (s.l.). Almost half of the records (n = 68, 48 %) of non-native tick
species from 2010 to 2019 represented ticks found on a host (usually a dog or a
human) that had traveled outside of Alaska in the two weeks prior to collection.
However, A. americanum, D. variabilis, I. pacificus, I. texanus, and R.
sanguineus s.l. have been found on humans and domestic animals in Alaska without
reported recent travel. In particular, there is evidence to suggest that there
is local establishment of R. sanguineus s.l. in Alaska. A tick species
historically found in the state, I. angustus was frequently found on human and
dogs, suggesting a potential role as a bridge vector of pathogens. Given the
inconsistency of tick monitoring in Alaska over the past century, it is
difficult to draw many conclusions from temporal trends in the data. Continued
monitoring through the Alaska Submit-A-Tick Program will allow a more accurate
assessment of the changing risk of ticks and tick-borne diseases in the state
and provide information for setting clinical and public health guidelines for
tick-borne disease prevention. The distribution and prevalence of zoonotic pathogens infecting ixodid ticks in
Western Europe have been extensively examined. However, data on ticks and
tick-borne pathogens in Eastern Europe, particularly Ukraine are scarce. The
objective of the current study was, therefore, to investigate the prevalence of
Anaplasma phagocytophilum, Anaplasmataceae, Rickettsia spp., Babesia spp.,
Bartonella spp., and Borrelia burgdorferi sensu lato in engorged and questing
ixodid ticks collected from five administrative regions (oblasts) of Ukraine,
namely Chernivtsi, Khmelnytskyi, Kyiv, Ternopil, and Vinnytsia. The ticks were
collected from both wild and domestic animals and from vegetation. Of 524 ixodid
ticks collected, 3, 99, and 422 ticks were identified as Ixodes hexagonus,
Ixodes ricinus, and Dermacentor reticulatus, respectively. DNA samples
individually extracted from 168 questing and 354 engorged adult ticks were
subjected to pathogen-specific PCR analyses. The mean prevalence in I. ricinus
and D. reticulatus were, respectively: 10 % (10/97) and 3 % (12/422) for A.
phagocytophilum; 69 % (67/97) and 52 % (220/422) for members of the
Anaplasmataceae family; 25 % (24/97) and 28 % (117/422) for Rickettsia spp.; 3 %
(3/97) and 1 % (6/422) for Babesia spp.; and 9 % (9/97) and 5 % (20/422) for
Bartonella spp. Overall, between the five cities, there was no significant
difference in the prevalence of any of the pathogens for the respective ticks (p
> 0.05). The prevalence of B. burgdorferi s. l. in the questing and engorged I.
ricinus varied from 0 to 27 % and 14-44%, respectively, with no statistical
significance identified between the five cities (p > 0.05). In addition to
reporting the updated data for Kyiv and Ternopil, this study is the first to
provide the prevalences of the tick-borne pathogens for Chernivtsi,
Khmelnytskyi, and Vinnytsia. This investigation is also the first to detect
Neoehrlichia mikurensis in ixodid ticks from Ukraine. These new data will be
useful for medical and veterinary practitioners as well as public health
officials when diagnosing infections and when implementing measures to combat
tick-borne diseases in Ukraine. |
What is the active ingredient in the most common hand sanitizer? | Evaluation of a benzalkonium chloride hand sanitizer in reducing transient Staphylococcus aureus bacterial skin contamination in health care workers. | BACKGROUND: Alcohol-based hand rubs (ABHRs) are the primary method of hand
hygiene in health-care settings. ICPs increasingly are assessing ABHR product
efficacy data as improved products and test methods are developed. As a result,
ICPs need better tools and recommendations for how to assess and compare ABHRs.
METHODS: Two ABHRs (70% ethanol) were tested according to 3 in vivo methods
approved by ASTM International: E1174, E2755, and E2784. Log10 reductions were
measured after a single test product use and after 10 consecutive uses at an
application volume of 2 mL.
RESULTS: The test method used had a significant influence on ABHR efficacy;
however, in this study the test product (gel or foam) did not significantly
influence efficacy. In addition, for all test methods, log10 reductions obtained
after a single application were not predictive of results after 10 applications.
CONCLUSIONS: Choice of test method can significantly influence efficacy results.
Therefore, when assessing antimicrobial efficacy data of hand hygiene products,
ICPs should pay close attention to the test method used, and ensure that product
comparisons are made head to head in the same study using the same test
methodology. Enteric protozoan parasites, which are spread by the fecal-oral route, are
important causes of diarrhea (Giardia duodenalis) and amebic dysentery
(Entamoeba histolytica). Cyst walls of Giardia and Entamoeba have a single layer
composed of fibrils of β-1,3-linked GalNAc and β-1,4-linked GlcNAc (chitin),
respectively. The goal here was to determine whether hand sanitizers that
contain ethanol or isopropanol as the active microbicide might reduce
transmission of these parasites. We found that treatment with these alcohols
with or without drying in a rotary evaporator (to model rapid evaporation of
sanitizers on hands) kills 85 to 100% of cysts of G. duodenalis and 90 to 100%
of cysts of Entamoeba invadens (a nonpathogenic model for E. histolytica), as
shown by nuclear labeling with propidium iodide and failure to excyst in vitro.
Alcohols with or without drying collapsed the cyst walls of Giardia but did not
collapse the cyst walls of Entamoeba. To validate the in vitro results, we
showed that treatment with alcohols eliminated oral infection of gerbils by
1,000 G. duodenalis cysts, while a commercial hand sanitizer (Purell) killed E.
invadens cysts that were directly applied to the hands. These results suggest
that expanded use of alcohol-based hand sanitizers might reduce the transmission
of Giardia and Entamoeba. BACKGROUND: We hypothesized that the addition of a novel verbal electronic audio
reminder to an educational patient hand hygiene bundle would increase
performance of self-managed patient hand hygiene.
METHODS: We conducted a 2-group comparative effectiveness study randomly
assigning participants to patient hand hygiene bundle 1 (n = 41), which included
a video, a handout, and a personalized verbal electronic audio reminder (EAR)
that prompted hand cleansing at 3 meal times, or patient hand hygiene bundle 2
(n = 34), which included the identical video and handout, but not the EAR. The
primary outcome was alcohol-based hand sanitizer use based on weighing bottles
of hand sanitizer.
RESULTS: Participants that received the EAR averaged significantly more use of
hand sanitizer product over the 3 days of the study (mean ± SD, 29.97 ± 17.13 g)
than participants with no EAR (mean ± SD, 10.88 ± 9.27 g; t73 = 5.822;
P ≤ .001).
CONCLUSIONS: The addition of a novel verbal EAR to a patient hand hygiene bundle
resulted in a significant increase in patient hand hygiene performance. Our
results suggest that simple audio technology can be used to improve patient
self-management of hand hygiene. Future research is needed to determine if the
technology can be used to promote other healthy behaviors, reduce infections,
and improve patient-centered care without increasing the workload of health care
workers. BACKGROUND: Infection control is a critical aspect in the continuum of surgical
care. Much of what is outlined in the literature pertains to hospital-based
practice, with only recent attention paid to the more austere environments,
particularly those faced during humanitarian or combat operations.
OBJECTIVE: This manuscript provides a brief historical review of the development
of infection control practices and further identifies and outlines several
aspects necessary to successful program applications in austere environments.
RESULTS: Hand hygiene remains the simplest form of infection control. Use of
alcohol-based hand sanitizer is a logistically reasonable option for most
circumstances, mitigating the requirement for clean running water to facilitate
more traditional "soap and water" methods of hand disinfection. Environmental
decontamination, patient cohorting, and patient isolation based on existing
colonization/infection also has demonstrated efficacy in controlling
cross-contamination and is feasible in most austere environments. Finally,
senior leadership engagement with deliberate planning, antimicrobial
stewardship, and vigorous quality and process improvement algorithms have
resulted in reduced rates of critical infections in these settings.
CONCLUSIONS: Basic tenets of infection control can be achieved even in
resource-poor environments. Meticulous attention to adhering to these
principles, with support from senior medical and operational leadership,
facilitates improvements in infection control outcomes. There remains, however,
a need for additional robust outcomes data regarding best practices in these
environments. Purpose: Adenoviral conjunctivitis is the most common cause of conjunctivitis
worldwide with no approved antiviral treatment. Benzalkonium chloride (BAK) is a
common preservative in ophthalmic medications and is the active ingredient in
some skin disinfectants and hand sanitizers. BAK is known to be effective in
killing bacteria and enveloped viruses; however, its activity against ocular
types of nonenveloped adenoviruses (Ads) is unknown. The goal was to determine
whether BAK is an effective antiviral agent against common human ocular types of
adenovirus in vitro. Methods: The direct inactivating activity of BAK was
determined by incubating several human adenovirus types with BAK concentrations
of 0.001%, 0.003%, 0.005%, 0.01%, 0.1%, and 0% for 1 h at 33°C. Resulting
adenovirus titers were determined after treatment. Decreases in titers of ≥3
Log10 were considered virucidal, while decreases in titers of <1 Log10 were
considered ineffective. Results: BAK 0.1% was virucidal for Ad3, Ad5, Ad7a,
Ad19/64, and Ad37, while it reduced titers >1 Log10, but <3 Log10 for Ad4 and
Ad8. Decreases in titers >1 Log10 were demonstrated for BAK 0.003%, 0.005%, and
0.01% for Ad5 only. Decreases in titers for the other adenovirus types for those
concentrations were ≤0.53 Log10. 0.001% BAK produced minimal decreases in titers
for all types. Conclusions: BAK, at 0.01% or less was not consistently effective
as an antiviral against adenovirus, but higher concentrations, such as 0.1%,
should be further investigated as a possible topical treatment for adenoviral
ocular infections, providing ocular toxicity is not an issue. BACKGROUND: This study was performed to evaluate the effectiveness of a new
commercially available hand sanitizer using 0.12% benzalkonium chloride (BZK) as
the active ingredient in reducing transient skin contamination with
Staphylococcus aureus in health care workers (HCWs), as compared with the
effectiveness of a 70% ethanol-based hand sanitizer.
METHODS: Fingertip touch culture plates were obtained from 40 HCWs in which all
HCWs used antimicrobial soap containing 0.6% chloroxylenol for handwashing
according to the Centers for Disease Control and Prevention guidelines for the
entire study, while continuing to use the 70% ethanol-based hand sanitizer
according to the Centers for Disease Control and Prevention guidelines for the
first week. After the first week, the test subjects used the BZK hand sanitizer
in place of the ethanol sanitizer. A paired sample t test was conducted to
compare the mean bacterial colonies grown from HCWs fingertips during the use of
the BZK and ethanol hand sanitizer.
RESULTS: The results showed a significant reduction in total bacterial colony
counts of S aureus during the week of BZK use as compared with the week of 70%
ethanol sanitizer use.
CONCLUSIONS: There was a significant decrease in transient S aureus on the
fingertips of HCWs in the BZK hand sanitizer use week as compared with the 70%
ethanol hand sanitizer use week. As a result of the coronavirus disease pandemic, commercial hand hygiene
products have become scarce and World Health Organization (WHO) alcohol-based
hand rub formulations containing ethanol or isopropanol are being produced for
hospitals worldwide. Neither WHO formulation meets European Norm 12791, the
basis for approval as a surgical hand preparation, nor satisfies European Norm
1500, the basis for approval as a hygienic hand rub. We evaluated the efficacy
of modified formulations with alcohol concentrations in mass instead of volume
percentage and glycerol concentrations of 0.5% instead of 1.45%. Both modified
formulations met standard requirements for a 3-minute surgical hand preparation,
the usual duration of surgical hand treatment in most hospitals in Europe.
Contrary to the originally proposed WHO hand rub formulations, both modified
formulations are appropriate for surgical hand preparation after 3 minutes when
alcohol concentrations of 80% wt/wt ethanol or 75% wt/wt isopropanol along with
reduced glycerol concentration (0.5%) are used. Since the onset of the COVID-19 pandemic, there has been an advisory for regular
and thorough cleaning of hands besides other measures such as social distancing
and self-isolation. The rationale for the same is to prevent the transfer of the
virus from hands that have come in contact with fomites. While both
alcohol-based hand rubs (ABHR) or washing with soap and water are claimed to
have been effective, hand sanitizers have gained more popularity due to the ease
of use. The increased frequency of ABHR use and the aerosols generated pose a
potential threat to the skin and exposed mucosal surfaces, especially that of
the eye due to the proximity of use. The adverse effects of alcohol in these
sanitizers can be manifold. An allergic or inflammatory response can occur
depending on the predisposing or preexisting conditions. This article describes
the risks, underlying mechanisms, and preventive measures for sanitizer
aerosol-driven ocular surface disease. Alcohol-based hand sanitizer is a liquid, gel, or foam that contains ethanol or
isopropanol used to disinfect hands. Hand hygiene is an important component of
the U.S. response to the emergence of SARS-CoV-2, the virus that causes
coronavirus disease 2019 (COVID-19). If soap and water are not readily
available, CDC recommends the use of alcohol-based hand sanitizer products that
contain at least 60% ethyl alcohol (ethanol) or 70% isopropyl alcohol
(isopropanol) in community settings (1); in health care settings, CDC
recommendations specify that alcohol-based hand sanitizer products should
contain 60%-95% alcohol (≥60% ethanol or ≥70% isopropanol) (2). According to the
Food and Drug Administration (FDA), which regulates alcohol-based hand
sanitizers as an over-the-counter drug, methanol (methyl alcohol) is not an
acceptable ingredient. Cases of ethanol toxicity following ingestion of
alcohol-based hand sanitizer products have been reported in persons with alcohol
use disorder (3,4). On June 30, 2020, CDC received notification from public
health partners in Arizona and New Mexico of cases of methanol poisoning
associated with ingestion of alcohol-based hand sanitizers. The case reports
followed an FDA consumer alert issued on June 19, 2020, warning about specific
hand sanitizers that contain methanol. Whereas early clinical effects of
methanol and ethanol poisoning are similar (e.g., headache, blurred vision,
nausea, vomiting, abdominal pain, loss of coordination, and decreased level of
consciousness), persons with methanol poisoning might develop severe anion-gap
metabolic acidosis, seizures, and blindness. If left untreated methanol
poisoning can be fatal (5). Survivors of methanol poisoning might have permanent
visual impairment, including complete vision loss; data suggest that vision loss
results from the direct toxic effect of formate, a toxic anion metabolite of
methanol, on the optic nerve (6). CDC and state partners established a case
definition of alcohol-based hand sanitizer-associated methanol poisoning and
reviewed 62 poison center call records from May 1 through June 30, 2020, to
characterize reported cases. Medical records were reviewed to abstract details
missing from poison center call records. During this period, 15 adult patients
met the case definition, including persons who were American Indian/Alaska
Native (AI/AN). All had ingested an alcohol-based hand sanitizer and were
subsequently admitted to a hospital. Four patients died and three were
discharged with vision impairment. Persons should never ingest alcohol-based
hand sanitizer, avoid use of specific imported products found to contain
methanol, and continue to monitor FDA guidance (7). Clinicians should maintain a
high index of suspicion for methanol poisoning when evaluating adult or
pediatric patients with reported swallowing of an alcohol-based hand sanitizer
product or with symptoms, signs, and laboratory findings (e.g., elevated
anion-gap metabolic acidosis) compatible with methanol poisoning. Treatment of
methanol poisoning includes supportive care, correction of acidosis,
administration of an alcohol dehydrogenase inhibitor (e.g., fomepizole), and
frequently, hemodialysis. |
Which was the first oral drug for the treatment of multiple sclerosis by the US Food and Drug Administration (FDA)? | FTY720 (Fingolimod) was approved as the first oral drug for the treatment of multiple sclerosis by the US Food and Drug Administration (FDA) in 2010. | FTY720 (Fingolimod) is a known sphingosine-1-phosphate (S1P) receptor agonist
that exerts strong anti-inflammatory effects and was approved as the first oral
drug for the treatment of multiple sclerosis by the US Food and Drug
Administration (FDA) in 2010. FTY720 is mainly associated with unique functional
"antagonist" and "agonist" mechanisms. The functional antagonistic mechanism is
mediated by the transient down-regulation and degradation of S1P receptors on
lymphocytes, which prevents lymphocytes from entering the blood stream from the
lymph node. This subsequently results in the development of lymphopenia and
reduces lymphocytic inflammation. Functional agonistic mechanisms are executed
through S1P receptors expressed on the surface of various cells including
neurons, astrocytes, microglia, and blood vessel endothelial cells. These
functions might play important roles in regulating anti-apoptotic systems,
modulating brain immune and phagocytic activities, preserving the
Blood-Brain-Barrier (BBB), and the proliferation of neural precursor cells.
Recently, FTY720 have shown receptor-independent effects, including
intracellular target bindings and epigenetic modulations. Many researchers have
recognized the positive effects of FTY720 and launched basic and clinical
experiments to test the use of this agent against stroke. Although the mechanism
of FTY720 has not been fully elucidated, its efficacy against cerebral stroke is
becoming clear, not only in animal models, but also in ischemic stroke patients
through clinical trials. In this article, we review the data obtained from
laboratory findings and preliminary clinical trials using FTY720 for stroke
treatment. |
Which S1P receptors does fingolimod bind to? | Pharmacologically, fingolimod has been characterized as a non-selective agonist of all of the S1P receptors (S1PR), with the exception of S1P2. | |
What was fingolimod synthesized from? | FTY720 (fingolimod, Gilenya®) was synthesized from myriocin, one of the metabolites of the fungus Isaria sinclairii known from traditional Chinese medicine for its antibacterial and energy boosting effect. | |
What does fingolimod do to the grey matter of the brain? | Fingolimod has been shown to reduce/prevent both focal and diffuse grey matter (GM) damage in active multiple sclerosis. The percentage of patients with new cortical lesions (CL) (13.5 vs. 89%, p < 0.001) and the percentage of GM volume change was lower in the fingolimod treated group (p < 0.001). The regional analysis revealed that the treated group had also less volume loss in thalamus, caudatus, globus pallidus, cingulate cortex, and hippocampus (p < 0.001), as well as in, cerebellum, superior frontal gyrus, and insular-long gyrus (p < 0.05). | INTRODUCTION: The mechanism of action of fingolimod within the central nervous
system and its efficacy in reducing/preventing both focal and diffuse grey
matter (GM) damage in active multiple sclerosis (MS) are not completely
understood.
METHODS: In this longitudinal, 2-year prospective, phase IV, single-blind study,
40 MS patients treated with fingolimod and 39 untreated age, gender, and
disability-matched MS patients were enrolled. Each patient underwent a
neurological examination every 6 months and a 3T MRI at the beginning of the
treatment and after 24 months. The accumulation of new cortical lesions (CLs)
and the progression of regional GM atrophy were compared between the two groups.
RESULTS: At the end of the study (T24), the percentage of patients with new CLs
(13.5 vs. 89%, p < 0.001) and the percentage of GM volume change was lower in
the treated group (p < 0.001). The regional analysis revealed that the treated
group had also less volume loss in thalamus, caudatus, globus pallidus,
cingulate cortex, and hippocampus (p < 0.001), as well as in, cerebellum,
superior frontal gyrus, and insular-long gyrus (p < 0.05). Patients with no
evidence of disease activity were 60% in the treated group and 10% in the
untreated group (p < 0.001).
CONCLUSIONS: These results suggest a possible protective effect of fingolimod on
focal and diffuse GM damage. |
What doses of fingolimod were administered during the FREEDOMS trial? | In the FREEDOMS trial fingolimod was administered at 0.5mg or 1.25mg doses. | BACKGROUND: Fingolimod 0·5 mg once daily is approved for treatment of relapsing
multiple sclerosis (MS). In the phase 3, 2-year FREEDOMS (FTY720 Research
Evaluating Effects of Daily Oral therapy in MS) study, fingolimod significantly
reduced annualised relapse rates (ARRs) and the risk of confirmed disability
progression compared with placebo. We aimed to investigate whether the
beneficial treatment effect reported for the overall population is consistent in
subgroups of patients with different baseline characteristics.
METHODS: We did subgroup analyses of ARRs (primary outcome) and confirmed
disability progression (a secondary outcome) over 24 months in the FREEDOMS
study, a randomised, double-blind study that included 1272 patients with
relapsing-remitting MS who were assigned 1:1:1 to fingolimod (0·5 mg or 1·25 mg)
or placebo once daily for 24 months. Subgroups were predefined, predefined and
slightly modified, or defined post hoc, by demographic factors (including sex
and age), disease characteristics (including baseline disability scores, relapse
rates, and lesion parameters), and response to previous therapy (including
analyses in patients eligible for fingolimod treatment according to the European
label). Data were analysed by intention to treat. The FREEDOMS study is
registered with ClinicalTrials.gov, number NCT00289978.
FINDINGS: Treatment with fingolimod 0·5 mg was associated with significantly
lower ARRs versus placebo across all subgroups except for patients aged over 40
years. ARR ratios ranged from 0·76 (95% CI 0·54-1·09; p=0·13) in patients aged
over 40 years to 0·29 (0·16-0·52; p<0·0001) in patients who had relapse activity
despite receiving interferon beta during the year before study enrolment. Hazard
ratios for confirmed disability progression over 24 months with fingolimod 0·5
mg versus placebo ranged from 0·85 (95% CI 0·53-1·36; p=0·50) in patients with a
T2 lesion volume of 3300 mm(3) or less to 0·32 (0·14-0·73; p=0·0066) in patients
with an EDSS over 3·5. In patients who relapsed and had lesion activity despite
treatment with interferon beta in the previous year, the ARR ratio for
fingolimod 0·5 mg versus placebo was 0·38 (95% CI 0·21-0·68, p=0·0011), and for
treatment-naive patients with rapidly evolving severe disease it was 0·33
(0·18-0·62, p=0·0006). Hazard ratios for confirmed disability progression over
24 months were 0·68 (0·29-1·62; p=0·39) and 0·73 (0·25-2·07; p=0·55),
respectively, in these groups.
INTERPRETATION: Patients with relapsing-remitting MS with a wide spectrum of
clinical and MRI features including subgroups specified by the European label
can potentially benefit from treatment with 0·5 mg fingolimod.
FUNDING: Novartis. |
How many patients were enrolled in the FREEDOMS clinical trial? | FREEDOMS study, a randomised, double-blind study included 1272 patients with relapsing-remitting MS. | BACKGROUND: Fingolimod 0·5 mg once daily is approved for treatment of relapsing
multiple sclerosis (MS). In the phase 3, 2-year FREEDOMS (FTY720 Research
Evaluating Effects of Daily Oral therapy in MS) study, fingolimod significantly
reduced annualised relapse rates (ARRs) and the risk of confirmed disability
progression compared with placebo. We aimed to investigate whether the
beneficial treatment effect reported for the overall population is consistent in
subgroups of patients with different baseline characteristics.
METHODS: We did subgroup analyses of ARRs (primary outcome) and confirmed
disability progression (a secondary outcome) over 24 months in the FREEDOMS
study, a randomised, double-blind study that included 1272 patients with
relapsing-remitting MS who were assigned 1:1:1 to fingolimod (0·5 mg or 1·25 mg)
or placebo once daily for 24 months. Subgroups were predefined, predefined and
slightly modified, or defined post hoc, by demographic factors (including sex
and age), disease characteristics (including baseline disability scores, relapse
rates, and lesion parameters), and response to previous therapy (including
analyses in patients eligible for fingolimod treatment according to the European
label). Data were analysed by intention to treat. The FREEDOMS study is
registered with ClinicalTrials.gov, number NCT00289978.
FINDINGS: Treatment with fingolimod 0·5 mg was associated with significantly
lower ARRs versus placebo across all subgroups except for patients aged over 40
years. ARR ratios ranged from 0·76 (95% CI 0·54-1·09; p=0·13) in patients aged
over 40 years to 0·29 (0·16-0·52; p<0·0001) in patients who had relapse activity
despite receiving interferon beta during the year before study enrolment. Hazard
ratios for confirmed disability progression over 24 months with fingolimod 0·5
mg versus placebo ranged from 0·85 (95% CI 0·53-1·36; p=0·50) in patients with a
T2 lesion volume of 3300 mm(3) or less to 0·32 (0·14-0·73; p=0·0066) in patients
with an EDSS over 3·5. In patients who relapsed and had lesion activity despite
treatment with interferon beta in the previous year, the ARR ratio for
fingolimod 0·5 mg versus placebo was 0·38 (95% CI 0·21-0·68, p=0·0011), and for
treatment-naive patients with rapidly evolving severe disease it was 0·33
(0·18-0·62, p=0·0006). Hazard ratios for confirmed disability progression over
24 months were 0·68 (0·29-1·62; p=0·39) and 0·73 (0·25-2·07; p=0·55),
respectively, in these groups.
INTERPRETATION: Patients with relapsing-remitting MS with a wide spectrum of
clinical and MRI features including subgroups specified by the European label
can potentially benefit from treatment with 0·5 mg fingolimod.
FUNDING: Novartis. |
What is blepharospasm? | The neurophysiological disruptions underlying blepharospasm, a disabling movement disorder characterized by increased blinking and involuntary muscle spasms of the eyelid, remain poorly understood. | Blepharospasm is a cranial nerve dysfunction in which involuntary and
uncontrollable forcible lid closure occurs. Surgical treatment is far from
ideal, but the condition can be improved by sectioning the branches of the
facial nerve plexus which supply the orbicularis oculi, the frontalis and
corrugator muscles, and the midfacial muscles. Not all patients with
blepharospasm should be operated upon, since they may expect too much or may
enjoy the attention their invalidism has given them. Ectropion of one or both
lower lids may occur, and the most severe of all complications is recurrence.
This may happen despite a careful microscopic search for the nerve fibers and
their division and avulsion. Blepharospasm patients often require considerable
psychological support. Primary blepharospasm is an adult-onset focal dystonia characterised by
involuntary contractions of the orbicularis oculi muscles. Patients may have
various types of movements arising from the different parts of the orbicularis
oculi muscle. These include typical blepharospasm associated with Charcot's
sign, pretarsal blepharospasm and flickering of the eyelids. Primary
blepharospasm may be associated with so-called apraxia of eyelid opening as well
as dystonia in the lower face, jaw or cervical muscles. Unless there are
clinical clues to a symptomatic cause, adults presenting with blepharospasm do
not require extensive aetiological investigation because the condition is rarely
due to an identifiable condition. As the aetiology of primary blepharospasm is
largely unknown, therapeutic approaches are symptomatic, with type A botulinum
toxin being the treatment of choice. BACKGROUND: Primary blepharospasm is a focal dystonia characterised by excessive
involuntary closure of the eyelids. The pathophysiology of primary blepharospasm
is unresolved.
AIM: To pinpoint grey-matter changes that are associated with primary
blepharospasm.
METHODS: 16 right-handed patients with primary blepharospasm (mean age 67.4 (SD
4.3) years; 12 women) were compared with 16 healthy volunteers matched for sex
and age. High-resolution T1-weighted magnetic resoce imaging of each
participant was obtained and analysed by voxel-based morphometry, a method to
detect regionally specific differences in grey matter between patients and
control group. To evaluate whether the identified grey-matter changes were
correlated with the duration of primary blepharospasm or botulinum neurotoxin
treatment (BoNT), separate regression analyses were carried out.
RESULTS: In patients with primary blepharospasm, grey-matter increase in the
putamina was observed, whereas regression analyses did not indicate a
correlation between grey-matter increases and the duration of primary
blepharospasm or BoNT. Grey-matter decrease was detected in the left inferior
parietal lobule; here regression analyses of grey-matter decrease showed a
significant (p = 0.013) correlation of grey-matter decrease with the duration of
BoNT.
CONCLUSIONS: The data suggest structural changes in primary blepharospasm and
point to a crucial role of the putamen for the pathophysiology of this focal
dystonia. BACKGROUND: Blepharospasm is an adult-onset focal dystonia that causes
involuntary blinking and eyelid spasms. Studies have shown the presence of
sensory deficits associated with dystonia.
AIM: To rule out any confounding effect of muscle spasms on sensory performance
in affected and unaffected body regions of patients with blepharospasm and with
hemifacial spasm.
METHODS: Participants (19 patients with blepharospasm, 19 patients with
hemifacial spasm and 19 control subjects) were asked to discriminate between two
stimuli that were either simultaneous or sequential (temporal discrimination
threshold, TDT). Pairs of tactile stimuli were delivered with increasing or
decreasing inter-stimulus intervals from 0 to 400 ms (in 10-ms steps) to the
hands or on the skin over the orbicularis oculi muscle.
RESULTS: Tactile stimuli elicited similar TDTs in control subjects and patients
with hemifacial spasm, but significantly higher TDTs in patients with
blepharospasm, regardless of whether stimuli were applied to the orbicularis
muscle or the hand.
CONCLUSIONS: As TDT was abnormal in unaffected body regions of patients with
blepharospasm, and patients with hemifacial spasm processed tactile stimuli
normally, TDT deficits in blepharospasm depend on central rather than peripheral
factors. This study further supports the link between focal dystonia and
impaired temporal processing of somatosensory inputs. Benign essential blepharospasm is characterized by abnormal repetitive movements
of lid closure and spasm of the orbiculari oculi muscles. Modern theories
postulate that this movement disorder originates by abnormal processing of
afferent information with further disintegration of the sensorimotor neural
program at central levels of the nervous system all of which is seen as dystonic
movements in genetically susceptible people. Different investigations including
neuroimagin, genetic and neurophysiological studies have discovered new findings
on what structures are involved and how this abnormal movement is generated.
Among these research is noteworthy the study of electrically elicited blink
reflex. It consists of three responses called non-nociceptive (R1), nociceptive
(R2) and ultranociceptive (R3). Such blink reflexes, mostly the ultranociceptive
response (R3), seem to be very useful to understand more deeply the
pathophysiology of this focal dystonia, to perform the functional
endophenotyping and to do a more appropriate follow-up of this complex
neurological problem. Essential blepharospasm is a facial dystonia characterized by spontaneous,
spasmodic and involuntary contractions of the eyelid muscles. In advanced cases,
blepharospasm patients develop severe eyelid spasms that render them
functionally blind, socially reclusive, and unable to work or care for
themselves. Oculoplastic surgeons frequently have to deal with patients with
blepharospasm. The decrease in quality of life caused by this pathology drives
all the attention to the resolution of the spasms. However, other conditions may
be associated with them and must be kept in mind during the ophthalmological
examination. Four patients with essential blepharospasm were diagnosed as
glaucomatous during their follow-up at the Oculoplastic Service. All of them
showed glaucomatous optic neuropathy and corresponding visual field defect and
no clinically apparent secondary cause for their glaucoma. Forced eyelid closure
may lead to intraocular pressure peaks. These patients with blepharospasm
present repetitive and spasmodic eyelid contractions and the intraocular
pressure rise observed during eyelid squeezing could be an additional risk
factor for glaucomatous damage. Our case series suggest that patients with
blepharospasm should be seriously evaluated for glaucoma. Essential blepharospasm is an idiopathic disorder that consists of spontaneous,
spasmodic, and involuntary eyelid closure in the absence of ocular disease. Some
patients develop an inability to open their eyelids in the absence of
orbicularis spasms. These patients have essential blepharospasm combined with
apraxia of eyelid opening. Botulinum toxin injections are the treatment of
choice for blepharospasm but results may be insufficient, especially in cases
associated with apraxia. Apraxia can be treated surgically by levator
aponeurosis advancement, frontalis suspension, and upper myectomy. The authors
report the first browlift using polypropylene suture to manage eyelid apraxia
associated with blepharospasm as an alternative and minimally invasive
procedure. BACKGROUND: Blepharospasm is a form of focal dystonia that manifests as
repetitive involuntary closure of the eyes. The pathogenesis of blepharospasm
and the neuroanatomic substrates involved are not fully understood. Dysfunction
of the basal ganglia traditionally is presumed to be the main cause of most
forms of dystonia, but a growing body of evidence suggests that a network of
additional cortical and subcortical structures may be involved.
METHODS: The medical records of 1114 patients with blepharospasm seen over past
10 years at Emory University were reviewed to identify potentially contributing
brain lesions. A systematic review of the published literature was also
conducted to identify potentially contributing brain lesions.
RESULTS: Among patients with blepharospasm at Emory University, 18 had focal
lesions on imaging studies available for review. The literature review revealed
25 articles describing 30 additional cases of blepharospasm associated with
focal lesions. Among all 48 cases, lesions were found in multiple regions
including the thalamus (n=12), lower brainstem (n=11), basal ganglia (n=9),
cerebellum (n=9), midbrain (n=7), and cortex (n=1).
CONCLUSIONS: These data in combination with functional imaging studies of
primary blepharospasm support a model in which a network of different regions
plays a role in the pathogenesis of blepharospasm. Blepharospasm (BSP) is a rather distressing form of focal dystonia. Although
many aspects of its pathophysiological mechanisms are already known, we lack
fundamental evidence on etiology, prevention, and treatment. To advance in our
knowledge, we need to review what is already known in various aspects of the
disorder and use these bases to find future lines of interest. Some of the signs
observed in BSP are cause, while others are consequence of the disorder.
Non-motor symptoms and signs may be a cue for understanding better the disease.
Various cerebral sites have been shown to be functionally abnormal in BSP,
including the basal ganglia, the cortex, and the cerebellum. However, we still
do not know if the dysfunction or structural change affecting these brain
regions is cause or consequence of BSP. Further advances in neurophysiology and
neuroimaging may eventually clarify the pathophysiological mechanisms
implicated. In this manuscript, we aim to update what is known regarding
epidemiology, clinical aspects, and pathophysiology of the disorder and
speculate on the directions of research worth pursuing in the near future. Objectives Although primary dystonia is typically characterized as a movement
disorder, it is also associated with cognitive alterations in the domain of
executive functioning which may arise from changes in cortico-basal ganglia
circuits. Specifically, in comparison to healthy controls, patients with
dystonia show deficits in neuropsychological tests of cognitive flexibility.
However, it is unclear whether cognitive inflexibility is caused by the
pathomechanisms underlying primary dystonia or by confounding factors such as
depression or symptom-related distraction.Methods The present study aimed to
eliminate these confounds by examining cognitive flexibility in dystonia
patients and in patients with similar motor symptoms but without a comparable
central pathophysiology. Eighteen patients with primary blepharospasm, a common
form of dystonia affecting the muscles around the eyes, and 19 patients with
hemifacial spasm, a facial nerve disorder causing similar eyelid spasms,
completed a computerized version of the Wisconsin Card Sorting Test (cWCST). The
two groups were further compared on tests of global cognitive functioning,
psychiatric symptoms, health status, and impulsiveness. Results Blepharospasm
patients committed significantly more errors on the cWCST than patients with
hemifacial spasm. Group differences were most pronounced with regard to
integration errors, a measure of rule-inference processes on the cWCST.
Integration errors were also associated with impulsiveness in patients with
blepharospasm. Conclusions Primary blepharospasm is related to deficits in
cognitive flexibility, even when blepharospasm patients are compared with
patients who suffer from motor symptoms of non-dystonic origin. Our results
support the possibility that cognitive inflexibility results from the specific
pathophysiological processes underlying primary dystonia. (JINS, 2016, 22,
662-670). INTRODUCTION: Blepharospasm is a focal dystonia characterized by involuntary
cocontraction of the eyelid protractors, causing spasmodic closure of the
eyelids. Apraxia of eyelid opening is caused by an inability to initiate lid
opening without paralytic abnormality. Some studies suggest that patients with
either pure blepharospasm or blepharospasm associated with apraxia of eyelid
opening are more prone to developing Parkinson's disease.
METHODS: In our study, 123I-FP-CIT (DAT) SPECT was performed in 24 patients with
either pure blepharospasm or blepharospasm associated with apraxia of eyelid
opening and no signs of parkinsonism to identify dopaminergic dysfunction.
RESULTS: DAT-SPECT was abnormal in 11 (46%) cases (five patients with isolated
blepharospasm and six patients with blepharospasm associated with apraxia of
eyelid opening) whose mean disease duration was 11 years.
CONCLUSION: Our study revealed presynaptic dopaminergic dysfunction, as
determined by 123I-FP-CIT or DAT-SPECT, in nearly half of our blepharospasm
patients (with or without apraxia of eyelid opening). Thus, the presence of
blepharospasm might be an early sign of a parkinsonian syndrome. Blepharospasm, which is the most frequent cranial dystonia, is characterized
clinically by bilateral, synchronous, and symmetric involuntary orbicularis
oculi muscle contractions. Assessment of motor abnormalities in patients with
blepharospasm is an important issue in the clinical practice of movement
disorders. This video highlights the most important aspects in the clinical
evaluation of blepharospasm. We will show how we approach the main motor
abnormalities related to blepharospasm. Additional features that often
characterize blepharospasm, such as increased blinking, sensory tricks that can
transiently improve muscle spasms, and apraxia of eyelid opening will also be
discussed. Then, we will summarize the main aspects that differentiate patients
with blepharospasm from other conditions characterized by eyelid disturbances.
Finally, we will take into account the possible therapeutic implications of an
accurate clinical examination of patients. Author information:
(1)Movement Disorders Service and Section of Neurology, Institute for
Neurosciences, St. Luke's Medical Center, Quezon City, Philippines; Department
of Neurosciences, College of Medicine, Philippine General Hospital, University
of the Philippines Manila, Manila, Philippines. Electronic address:
[email protected].
(2)Department of Neurosciences, College of Medicine, Philippine General
Hospital, University of the Philippines Manila, Manila, Philippines; Department
of Clinical Epidemiology, College of Medicine, University of the Philippines
Manila, Philippines.
(3)Section of Neurology, Institute for Neurosciences, St. Luke's Medical Center,
Quezon City, Philippines.
(4)Section of Endocrinology, Department of Medicine, St. Luke's Medical Center,
Quezon City, Philippines. BACKGROUND: The neurophysiological disruptions underlying blepharospasm, a
disabling movement disorder characterized by increased blinking and involuntary
muscle spasms of the eyelid, remain poorly understood.
OBJECTIVE: To investigate the neural substrates underlying reflexive blinking in
blepharospasm patients compared to healthy controls using simultaneous
functional MRI and surface electromyography.
METHODS: Fifteen blepharospasm patients and 15 healthy controls were recruited.
Randomly timed air puffs to the left eye were used to induce reflexive eye
blinks during two 8-minute functional MRI scans. Continuous surface
electromyography and video recordings were used to monitor blink responses.
Imaging data were analyzed using an event-related design.
RESULTS: Fourteen blepharospasm patients (10 female; 61.6 ± 8.0 years) and 15
controls (11 female; 60.9 ± 5.5 years) were included in the final analysis.
Reflexive eye blinks in controls were associated with activation of the right
hippocampus and in patients with activation of the left caudate nucleus.
Reflexive blinks in blepharospasm patients showed increased activation in the
right postcentral gyrus and precuneus, left precentral gyrus, and left occipital
cortex compared to controls. Dystonia severity negatively correlated with
activity in the left occipital cortex, and disease duration negatively
correlated with reflexive-blink activity in the cerebellum.
CONCLUSIONS: Reflexive blinking in blepharospasm is associated with increased
activation in the caudate nucleus and sensorimotor cortices, suggesting a loss
of inhibition within the sensorimotor corticobasal ganglia network. The
association between decreasing neural response during reflexive blinking in the
cerebellum with disease duration suggests an adaptive role. © 2020 International
Parkinson and Movement Disorder Society. |
Explain the action of Balovaptan. | Balovaptan is a low-molecular-weight, orally active, hydrophilic non-peptide molecule that blocks Vasopressin-1a. It is approved for the treatment of autism spectrum disorders (ASD). | INTRODUCTION: Balovaptan, an investigational vasopressin 1a receptor antagonist
that has been evaluated for improvement of social communication and interaction,
is primarily metabolized by cytochrome P450 3A4 (CYP3A4).
METHODS: Two single-center, non-randomized, two-period, phase 1 studies assessed
the effect of the strong CYP3A4 inhibitor itraconazole (study NCT03579719) or
the strong CYP3A4 inducer rifampicin (study NCT03586726) at steady state on the
pharmacokinetics (PK) of steady-state balovaptan in healthy volunteers.
Participants received balovaptan (5 or 10 mg/day) alone for 10 days, or in
combination with itraconazole (200 mg/day) for 15 days, or rifampicin
(600 mg/day) for 10 days, following balovaptan washout and
itraconazole/rifampicin pre-dosing. Geometric mean ratios (GMRs) and 90%
confidence intervals (90% CIs) for the area under the concentration-time curve
over the dosing interval (AUC) and maximum plasma concentration (Cmax) of
balovaptan dosed with vs. without itraconazole/rifampicin were estimated from a
mixed effects model.
RESULTS: Both studies comprised 15-16 healthy male and female volunteers.
Itraconazole 200 mg/day elevated steady-state exposure to 5 mg/day balovaptan
approximately 4.5-5.5-fold (Day 15 GMR [90% CI], 4.46 [4.06-4.90] for Cmax and
5.57 [5.00-6.21] for AUC) and extended the time to steady state from ~ 5 days
to ~ 13-14 days. Rifampicin 600 mg/day resulted in ~ 90% reductions in both the
Cmax (Day 10 GMR [90% CI], 0.14 [0.12-0.15]) and AUC (0.07 [0.06-0.07]) of
balovaptan 10 mg/day. Time to balovaptan steady state could not be determined
with rifampicin. There were no clinically significant safety findings in either
study.
CONCLUSIONS: Strong modulators of CYP3A4 activity will significantly alter the
PK of balovaptan, with the effect of CYP3A4 induction greater than that of
inhibition. Caution should be taken when concomitantly dosing balovaptan with
moderate or strong CYP3A4 inducers or strong CYP3A4 inhibitors.
TRIAL REGISTRATION NUMBER: NCT03579719; NCT03586726. |
what is the effect of Bisphenol A in the body? | Bisphenol A (BPA) is an endocrine-disruptor compound that exhibits estrogenic activit | Bisphenol A is a widely used industrial chemical with many potential sources of
human exposure. Bisphenol A is a weak estrogen and has been implicated as an
"endocrine disruptor". This term is used for a variety of chemicals encountered
in the environment which have estrogenic activity. It has been postulated that
human exposure to these chemicals may elicit unwanted estrogenic effects in
humans such as reduced fertility, altered development and cancer. Up to now the
body burden of bisphenol A in humans is unknown. Therefore, we investigated the
metabolism and toxicokinetics of bisphenol A in humans exposed to low doses
since systemic bioavailability has a major influence on possible estrogenic
effects in vivo. Human subjects (three males and three females, and four males
for detailed description of blood kinetics) were administered d(16)-bisphenol A
(5 mg). Blood and urine samples were taken in intervals (up to 96 h),
metabolites formed were identified by GC/MS and LC-MS/MS and quantified by
GC/MS-NCI and LC-MS/MS. d(16)-Bisphenol A glucuronide was the only metabolite of
d(16)-bisphenol A detected in urine and blood samples, and concentrations of
free d(16)-bisphenol A were below the limit of detection both in urine (6 nM)
and blood samples (10 nM). d(16)-Bisphenol A glucuronide was cleared from human
blood and excreted with urine with terminal half-lives of less than 6 h; the
applied doses were completely recovered in urine as d(16)-bisphenol A
glucuronide. Maximum blood levels of d(16)-bisphenol A glucuronide
(approximately 800 nM) were measured 80 min after oral administration of
d(16)-bisphenol A (5 mg). The obtained data indicate major species differences
in the disposition of bisphenol A. Enterohepatic circulation of bisphenol A
glucuronide in rats results in a slow rate of excretion, whereas bisphenol A is
rapidly conjugated and excreted by humans due to the absence of enterohepatic
circulation. The efficient glucuronidation of bisphenol A and the rapid
excretion of the formed glucuronide result in a low body burden of the
estrogenic bisphenol A in humans following oral absorption of low doses. Bisphenol A has been shown to affect the reproduction of male rats and mice.
However, the mechanism of action of bisphenol A on the epididymal sperm is not
elucidated. The present study was undertaken to evaluate the effect of bisphenol
A on the antioxidant system of rat epididymal sperm. Bisphenol A was
administered orally to male rats at the dose levels of 0.2, 2 and 20 microg/Kg
body weight per day for 45 days. After 24 h of the last treatment, rats were
weighed and killed using anesthetic ether. The body weight of treated rats did
not show significant change as compared with the corresponding control groups.
In bisphenol A-treated rats there was a significant decrease in the weight of
the testis and epididymis; the weight of ventral prostate increased
significantly whereas there was no significant change in the weight of seminal
vesicles as compared with the corresponding group of control animals. Sperm
collected from the epididymis were used for sperm count and biochemical
estimations. Administration of bisphenol A caused a reduction in the epididymal
sperm motility and sperm count in a dose-dependent manner. The activities of
superoxide dismutase, catalase, glutathione reductase and glutathione peroxidase
were decreased while the levels of H(2)O(2) and lipid peroxidation increased
significantly in the treated rats as compared with the corresponding group of
control animals. The results suggested that graded doses of bisphenol A elicit
depletion of antioxidant defence system and induce oxidative stress in
epididymal sperm of rats. In conclusion, the adverse effect of bisphenol A on
male reproduction may be due to induction of oxidative stress in sperm. Bisphenol A, an environmental contamit, widely used as a monomer in
polycarbonate plastics, has been shown to cause abnormalities in liver of rats
and mice. The nature and mechanism of action of bisphenol A on liver is not
clear. The aim of the present study was to investigate if bisphenol A induces
oxidative stress in the liver of rats and if co-administration of vitamin C, an
antioxidant, can prevent oxidative stress. Bisphenol A (0.2, 2.0 and 20 micro
g/kg body weight per day) and bisphenol A+vitamin C (0.2, 2.0, 20 micro g+40
mg/kg body weight per day) was orally administered to rats for 30 days. After 24
h of the last treatment, rats were killed using overdose of anesthetic ether.
Body weights of the animals and the weights of liver showed no significant
changes. The activities of antioxidant enzymes, superoxide dismutase, catalase,
glutathione reductase and glutathione peroxidase were decreased in mitochondrial
and microsome-rich fractions of liver. The levels of hydrogen peroxide and lipid
peroxidation increased in the treated rats when compared with the corresponding
group of control animals. Activity of alanine transaminase, a marker enzyme of
hepatic injury remained unchanged in the treated rats as compared with the
corresponding control rats. Co-administration of bisphenol A and vitamin C
showed no changes in the activities of superoxide dismutase, catalase,
glutathione reductase and glutathione peroxidase and in the levels of hydrogen
peroxide and lipid peroxidation as compared with the corresponding control
groups. The results indicated that bisphenol A induces oxidative stress in the
liver of rats by decreasing the antioxidant enzymes. Co-administration of
vitamin C reversed the effects of bisphenol A-induced oxidative stress in the
liver of rats. Bisphenol A [BPA, 2,2-bis(4-hydoxyphenyl)propane], an industrial chemical used
in the production of polycarbonate, epoxide resin, and polyarylate, is
considered to be an endocrine-disrupting chemical. BPA may be present in some
hollow-fiber dialyzers used in hemodialysis. In this study, we tested the
amounts of BPA eluted from various hollow fibers. Furthermore, we measured the
BPA concentration in the sera of 22 renal disease predialysis patients, as well
as 15 patients who were receiving hemodialysis, to see if there is BPA
accumulation in these patients. The elution test of BPA showed that a much
larger amount of BPA was eluted from polysulfone (PS), and
polyester-polymeralloy hollow fibers. Among renal disease patients who had not
undergone hemodialysis, the serum BPA concentration increased as the renal
function deteriorated, showing a significant negative association. In a
crossover test between PS and cellulose (Ce) dialyzers, the predialysis serum
BPA concentration of PS dialyzer users decreased after changing to a Ce
dialyzer, and the serum BPA increased again after switching back to PS
dialyzers. In patients who were using PS dialyzers, the BPA level significantly
increased after a dialysis session. However, in the Ce dialyzer users, the BPA
level decreased. Since accumulation of BPA could affect the endocrine or
metabolic system of the human body, it is important to perform further
investigations on dialysis patients. By virtue of its binding to steroid hormone receptors, bisphenol A (BPA, the
unconjugated bioactive monomer) is hypothesized to be estrogenic when present in
sufficient quantities in the body, raising concerns that widespread exposure to
BPA may impact human health. To better understand the internal exposure of adult
humans to BPA and the relationship between the serum and urinary
pharmacokinetics of BPA, a clinical exposure study was conducted. Blood and
urine samples were collected approximately hourly over a 24-h period from 20
adult volunteers who ingested 100% of one of three specified meals comprising
standard grocery store food items for breakfast, lunch, and dinner. The
volunteers' average consumption of BPA, estimated from the urinary excretion of
total BPA ((TOT)BPA = conjugated BPA + BPA), was 0.27 μg/kg body weight (range,
0.03-0.86), 21% greater than the 95th percentile of aggregate exposure in the
adult U.S. population. A serum time course of (TOT)BPA was observable only in
individuals with exposures 1.3-3.9 times higher than the 95th percentile of
aggregate U.S. exposure. The (TOT)BPA urine concentration T(max) was 2.75 h
(range, 0.75-5.75 h) post-meal, lagging the serum concentration T(max) by ∼1 h.
Serum (TOT)BPA area under the curve per unit BPA exposure was between 21.5 and
79.0 nM•h•kg/μg BPA. Serum (TOT)BPA concentrations ranged from less than or
equal to limit of detection (LOD, 1.3 nM) to 5.7 nM and were, on average, 42
times lower than urine concentrations. During these high dietary exposures,
(TOT)BPA concentrations in serum were undetectable in 83% of the 320 samples
collected and BPA concentrations were determined to be less than or equal to LOD
in all samples. Bisphenol-A (BPA) is one of the most widespread endocrine disrupting chemicals
(EDC) used as the base compound in the manufacture of polycarbonate plastics.
Although evidence points to consider exposure to BPA as a risk factor for
insulin resistance, its actions on whole body metabolism and on
insulin-sensitive tissues are still unclear. The aim of the present work was to
study the effects of low doses of BPA in insulin-sensitive peripheral tissues
and whole body metabolism in adult mice. Adult mice were treated with
subcutaneous injection of 100 µg/kg BPA or vehicle for 8 days. Whole body energy
homeostasis was assessed with in vivo indirect calorimetry. Insulin signaling
assays were conducted by western blot analysis. Mice treated with BPA were
insulin resistant and had increased glucose-stimulated insulin release.
BPA-treated mice had decreased food intake, lower body temperature and locomotor
activity compared to control. In skeletal muscle, insulin-stimulated tyrosine
phosphorylation of the insulin receptor β subunit was impaired in BPA-treated
mice. This impairment was associated with a reduced insulin-stimulated Akt
phosphorylation in the Thr(308) residue. Both skeletal muscle and liver
displayed an upregulation of IRS-1 protein by BPA. The mitogen-activated protein
kinase (MAPK) signaling pathway was also impaired in the skeletal muscle from
BPA-treated mice. In the liver, BPA effects were of lesser intensity with
decreased insulin-stimulated tyrosine phosphorylation of the insulin receptor β
subunit.In conclusion, short-term treatment with low doses of BPA slows down
whole body energy metabolism and disrupts insulin signaling in peripheral
tissues. Thus, our findings support the notion that BPA can be considered a risk
factor for the development of type 2 diabetes. The "tolerable daily intake" of bisphenol A, established by the European and US
regulatory agencies, is based on a small number of reproductive toxicity studies
in animals, mostly funded by industry, using protocols that adhere to regulatory
guidelines. Many scientists consider these regulatory toxicology tests
unsuitable for the evaluation of endocrine disrupters, because they cannot be
used to demonstrate the effects of low doses of bisphenol A, observed in dozens
of independent studies. Results obtained in studies of high doses of bisphenol A
have been extrapolated to predict the effects of low-dose exposure, according to
the principle that "the dose makes the poison". The validity of this
extrapolation is disputed. Some human studies suggest that bisphenol A causes
coronary heart disease, increases the risk of type 2 diabetes, and has harmful
effects on reproduction and development. Considerable data from rodent studies
suggest that low doses of bisphenol A affect reproduction, lipid metabolism and
neurological development, usually following intrauterine or postnatal exposure.
In France, the use of bisphenol A in infant feeding bottles has been banned
since 30 June 2010, and in food packaging intended for children aged 0 to 3
years since 1 January 2013. The ban is due to be extended to all food packaging
as of 1 January 2015. Bisphenol A is not the only substance present in food
packaging that could interfere with endocrine function. Too little is known yet
about the toxicology of bisphenol A substitutes. Several studies have shown that
exposure to bisphenol A in adults and children can be greatly reduced by
choosing a varied diet based on fresh foods, and by avoiding the use of plastic
tableware. To reduce exposure to bisphenol A and other chemicals with hormonal
activity that are present in food packaging, it seems reasonable to encourage
the consumption of fresh foods, avoiding canned food and plastic packaging for
storing and reheating food and beverages. These precautionary measures are most
important for food and beverages intended for pregt women and young children. All of us now carry in our bodily tissues a virtual stew of heavy metals and
hundreds of synthetic chemicals: persistent ones, which can have a "half-life"
in the body of several years; and nonpersistent compounds, which may pass
through the body in a matter of hours. Bisphenol A (BPA) is a nonpersistent
compound that can alter the reproductive system of laboratory animals even at
extremely low exposure levels. This is relevant because BPA is chronically
present in our environment with the potential for constant exposure, making it
functionally equivalent to a persistent compound. In this review the authors
emphasize particular outcomes that occur in response to the relevant dose of BPA
exposure that causes developmental effects on reproductive systems, brain and
metabolic processes, and the male germ line. At a specific dose level, BPA
exposure also shows oxidative toxicity and carcinogenic effects. Bisphenol A (BPA) is a monomer found in plastic products used daily for the
storage and consumption of food and beverages, such as plastic bottles,
containers, and even toys. The molecule leaches out into the food, increasingly
if exposed to warm temperatures and high acidity. BPA is known for many negative
effects on the human body; for instance it acts as an xenoestrogen and
influences fertility and gestation and might also have carcinogenic effects,
causing breast and prostate cancer. Although it has not yet been proven as a
direct cause of autoimmunity, many of the effects of BPA can be related to the
pathogenesis of autoimmune disease (AID). Its estrogenic behavior modulates the
immune system, it encourages the secretion of Prolactin that is known to be
associated to AID, it creates oxidative stress that triggers the immune system
and so on. Therefore there is room to advise individuals at risk for AID to
avoid the consumption of BPA, similar to guidelines for pregt women. Bisphenol A is widely used in food contact materials and other products and is
detected in human urine and blood. Bisphenol A may affect reproductive and
neurological development; however, opinion of the European Food Safety Authority
(EFSA) on bisphenol A (EFSA J, 13, 2015 and 3978) concluded that none of the
available studies were robust enough to provide a point of departure for setting
a tolerable daily intake for bisphenol A. In the present study, pregt Wistar
rats (n = 17-21) were gavaged from gestation day 7 to pup day 22 with bisphenol
A doses of 0, 25 μg, 250 μg, 5 mg or 50 mg/kg bw/day. In the offspring, growth,
sexual maturation, weights and histopathology of reproductive organs, oestrus
cyclicity and sperm counts were assessed. Neurobehavioural development was
investigated using a behavioural testing battery including tests for motor
activity, sweet preference, anxiety and spatial learning. Decreased sperm count
was found at the lowest bisphenol A dose, that is 25 μg/kg/day, but not at the
higher doses. Reproductive organ weight and histology were not affected and no
behavioural effects were seen in male offspring. In the female offspring,
exposure to 25 μg/kg bw/day bisphenol A dose resulted in increased body weight
late in life and altered spatial learning in a Morris water maze, indicating
masculinization of the brain. Decreased intake of sweetened water was seen in
females from the highest bisphenol A dose group, also a possible sign of
masculinization. The other investigated endpoints were not significantly
affected. In conclusion, the present study using a robust experimental study
design, has shown that developmental exposure to 25 μg/kg bw/day bisphenol A can
cause adverse effects on fertility (decreased sperm count), neurodevelopment
(masculinization of spatial learning in females) and lead to increased female
body weight late in life. These results suggest that the new EFSA temporary
tolerable daily intake of 4 μg/kg bw/day is not sufficiently protective with
regard to endocrine disrupting effects of bisphenol A in humans. Bisphenol A, one of the industrial chemicals used in plastics and in the coating
of dishes and medical equipment, behaves as an endocrine disruptor in the human
body. Bisphenol A can bind directly to several types of nuclear receptors,
including steroid and xenobiotic receptor (SXR). SXR plays an important role in
bone metabolism through the activation of osteoblasts in vitro, but SXR protein
localization has not been reported in bone tissues. Additionally, it is not
known whether bisphenol A acts on osteoblasts through SXR activation. Therefore,
in this study, we first examined the immunolocalization of the SXR protein in
human adult and fetal bone tissues. We then examined the effects of bisphenol A
on human osteoblasts in vitro. SXR immunoreactivity was detected in osteoblasts,
but not in osteoclasts, of both adult and fetal bone tissues. In fetal bone
tissues, the mesenchymal cells or fetal connective tissue were also positive for
SXR immunoreactivity. Expression of SXR target genes (tsukushi, matrilin-2, and
CYP3A4) and SXR response element-luciferase activity were increased by bisphenol
A treatment in normal osteoblasts transfected with SXR (hFOB/SXR) and in
osteoblast-like cells (MG-63). Bisphenol A also stimulated cell proliferation
and collagen accumulation in hFOB/SXR cells. These results suggest that, as in
other tissues, SXR plays important roles in bone metabolism and fetal bone
development and that bisphenol A may disturb bone homeostasis in both adult and
fetus through SXR. Bisphenol A (BPA) can disrupt glucose homeostasis and impair pancreatic islet
function; however, the mechanisms behind these effects are poorly understood.
Male mice (4 wk old) were treated with BPA (50 or 500 μg/kg/d) for 8 wk.
Whole-body glucose homeostasis, pancreatic islet morphology and function, and
miR-338-mediated molecular signal transduction analyses were examined. We showed
that BPA treatment led to a disruption of glucose tolerance and a compensatory
increase of pancreatic islets insulin secretion and pancreatic and duodenal
homeobox 1 (Pdx1) expression in mice. Inhibition of Pdx1 reduced
glucose-stimulated insulin secretion and ATP production in the islets of
BPA-exposed mice. Based on primary pancreatic islets, we also confirmed that
miR-338 regulated Pdx1 and thus contributed to BPA-induced insulin secretory
dysfunction from compensation to decompensation. Short-term BPA exposure
downregulated miR-338 through activation of G-protein-coupled estrogen receptor
1 (Gpr30), whereas long-term BPA exposure upregulated miR-338 through
suppression of glucagon-like peptide 1 receptor (Glp1r). Taken together, our
results reveal a molecular mechanism, whereby BPA regulates Gpr30/Glp1r to
mediate the expression of miR-338, which acts to control Pdx1-dependent insulin
secretion. The Gpr30/Glp1r-miR-338-Pdx1 axis should be represented as a novel
mechanism by which BPA induces insulin secretory dysfunction in pancreatic
islets.-Wei, J., Ding, D., Wang, T., Liu, Q., Lin, Y. MiR-338 controls
BPA-triggered pancreatic islet insulin secretory dysfunction from compensation
to decompensation by targeting Pdx-1. Nowadays, endocrine disrupting chemical pollution has become one of the major
concerns due to the potential role of these chemicals in provoking endocrine
disorders especially type 2 diabetes. As a widespread endocrine disrupting
chemical, Bisphenol A, with modest estrogenic activity can exert its detrimental
effects in the different organs involved in type 2 diabetes such as pancreas,
liver, adipocyte and skeletal muscles. Obesity, hepatic steatosis, impaired
insulin signaling and pancreatic islet function could be the main results of
Bisphenol A exposure. Epigenetic dysregulations can be suggested as an important
underlying mechanism for Bisphenol A toxicity in the endocrine system. The most
studied genes in this respect, which are responsible for glucose homeostasis
include Pdx1, Gck, Igf2, Srebf1 and Srebf2. Aberrant DNA methylation, histone
demethylation and deacetylation and impaired miRNAs result in epigenetically
dysfunctional genes that finally distract the normal glucose regulation. The
present study aimed to summarize the general effects of prenatal and postnatal
Bisphenol A exposure on glucose metabolism focusing on animal studies and review
the recent investigations on Bisphenol A -induced epigenetic perturbations that
affect the normal glucose and lipid homeostasis and lead to type 2 diabetes. BACKGROUND: Bisphenol A (BPA) is a well-known endocrine disruptor that affects
male fertility. However, the main biological events through which BPA affects
spermatogenesis remain to be identified.
METHODS: Adult male mice were treated by feeding with drinking water containing
BPA (0.2 μg/ml, 20 μg/ml, 200 μg/ml, respectively) for two months. Testes were
collected for protein extraction or for immunohistochemical analysis. Epididymal
spermatozoa were collected for sperm quality evaluation and male fertility assay
by in vitro fertility (IVF). Serums were collected for detection of testosterone
levels. Proteins associated with germ cell proliferation, meiosis, blood-testis
barrier, and steroidogenesis production were examined in BPA-treated and control
mice testes. CCK8 assay was used to detect the effect of BPA on the
proliferation of GC-1 and GC-2 cells.
RESULTS: The BPA-treated mice were characterized by decreased sperm quality,
serum testosterone levels and, sub-fertile phenotype characterizing with low
pregcy rates and reduced fertilization efficiency. In lower BPA (0.2 μg/ml)
treatment, PCNA and PLZF were down-expressed that indicated impaired germ cell
proliferation. SYCP3 was down-expressed in BPA-treated mice, but expressions of
other proteins associated with meiosis and blood-testis barrier were not
significantly altered. CYP11A1 and HSD3B1 were down-expressed in BPA-treated
mice that demonstrated reduced steroidogenesis activity. BPA has a
concentration-dependent inhibition effect on the proliferation of GC-1 and
GC-2 cells. Conclusively, low doses BPA exposure reduced mice sperm quality
mainly by impairing germ cell proliferation, leading to reduced male fertility.
The study would provide relevant information for investigation on molecular
mechanisms and protective strategy on male production. Bisphenol A (BPA) is an endocrine-disruptor compound that exhibits estrogenic
activity. BPA is used in the production of materials such as polycarbonate
plastics, epoxy resins and dental sealants. Whereas, the endocrine modulating
activity of BPA and its effects on reproductive health have been widely studied,
its effects on the function of the immune system are poorly characterized. This
might be attributable to the different BPA doses used in a diversity of animal
models. Moreover, most studies of the effect of BPA on the immune response are
limited to in vitro and in vivo studies that have focused primarily on the
impact of BPA on the number and proportion of immune cell populations, without
evaluating its effects on immune function in response to an antigenic challenge
or infectious pathogens. In this review, we discuss the current literature on
the effects of BPA on the function of immune system that potentially increases
the susceptibility to infections by the virtue of acting as a pro-inflammatory
molecule. Thus, it appears that BPA, while by such an impact might be useful in
the control of certain disease states that are helped by an inflmmatory
response, it can worsen the prognosis of diseases that are adversely affected by
inflammation. Bisphenol A (BPA), a compound used in the manufacturing of plastics and epoxy
resins, is an endocrine disruptor with significant adverse impact on the human's
health. Here, we review the animal models and clinical studies as well as the
molecular and cellular mechanisms that show that BPA alters the normal function
of the reproductive system, metabolism, brain function and behavior and
contributes to the development of certain neurodevelopmental disorders including
autism spectrum and attention-deficit and hyperactivity disorders. BPA also
causes aberrant cognitive function, behavioral disturbances, and
neurodegenerative diseases, including Parkinson's disease, amyotrophic lateral
sclerosis (ALS), and multiple sclerosis. It has recently been proposed that
exposure to BPA may be associated with the development of certain
neurodegenerative diseases and neurodevelopmental disorders; however, it is a
line of research that is just emerging. This work aims to review the available
information about the association between exposure to BPA and cognitive
function, behavioral disturbances, neurodegenerative diseases (Parkinson�s
Disease, Amyotrophic lateral sclerosis, Multiple Sclerosis), and
neurodevelopmental disorders (Autism Spectrum and
Attention-Deficit/Hyperactivity Disorders). Likewise, the molecular and cellular
mechanisms that may be involved with these pathological conditions will be
analyzed. |
List the main proteins found in human saliva. | Amylases
Cystatins
Immunoglobulins
Mucins | Recent characterization of the whole saliva proteome led to contradictory
pictures concerning the complexity of its proteome. In this work, 110 proteins
were analysed by mass spectrometry allowing the identification of 10 accessions
previously not detected on protein two-dimensional maps, including myosin heavy
chain (fast skeletal muscle, IIA and IIB), phosphatidylethanolamine binding
protein, secretory actin-binding protein precursor and triosephosphate
isomerase. Further comparison with available data demonstrated simultaneously a
low diversity in terms of variety of accessions and a high complexity in terms
of number of protein spots identifying the same accession, the two thirds of
identified spots corresponding to amylases, cystatins and immunoglobulins. This
diversity may be of interest in the development of non invasive diagnostic tool
for several disease. The aim of our research was to evaluate redox balance parameters and biomarkers
of oxidative stress (OS) in nonstimulated and stimulated saliva as well as the
blood of patients with plaque psoriasis compared to healthy controls. The study
involved 40 patients with plaque psoriasis and 40 generally healthy subjects
matched by age and gender to the study group patients. We assayed the
concentration/activity of antioxidant enzymes: salivary peroxidase (Px),
catalase (CAT), and superoxide dismutase (SOD) measured in unstimulated saliva
(NWS), stimulated saliva (SWS), and erythrocytes. In plasma as well as NWS and
SWS, we measured the concentration/activity of reduced glutathione (GSH), total
antioxidant potential (TAC), total oxidative status (TOS), oxidative stress
index (OSI), and markers of oxidative modification of proteins: advanced
glycation end products (AGE), advanced oxidation protein products (AOPP), and
lipid oxidation products: malondialdehyde (MDA) and total lipid hydroperoxide
(LOOH). In NWS and SWS, we also evaluated the rate of reactive oxygen species
(ROS) production. The concentration of Px, CAT, and SOD was significantly higher
in NWS of patients with plaque psoriasis vs. healthy subjects. In SWS of
psoriatic patients, we observed considerably higher concentration of Px and CAT,
and in erythrocytes of patients with plaque psoriasis, the concentration of GPx
and CAT was significantly higher compared to that in the controls. The levels of
AOPP, AGE, MDA, and LOOH were considerably higher in NWS, SWS, and plasma of the
study group compared to the controls. The concentration of total protein and
salivary amylase was significantly lower in NWS and SWS of psoriatic patients
compared to the healthy control. In the course of plaque psoriasis, we observed
redox imbalances with prevalence of oxidation reactions. Mechanisms involved in
the synthesis/secretion of proteins and activity of amylase were depressed in
both glands of psoriatic patients; however, they were more inhibited in the
parotid gland compared to the submandibular gland. TOS concentration and OSI
value in NWS and SWS may serve as diagnostic biomarkers of plaque psoriasis. It is widely recognized that smelling food results in a mouth-watering feeling
and influences appetite. However, besides changes in volume, little is known
about the effects that food odours have on the composition of saliva. The aim of
the present study was to access the effects that smelling bread has on saliva
proteome and to compare such effects with those of chewing and ingesting it.
Besides a significant increase in saliva flow rate, together with a decrease in
total protein concentration, bread odour induced changes in the proportion of
different salivary proteins. The expression levels of two spots of cystatins and
two spots of amylase increased due to olfactory stimulation, similar to what
happened with bread mastication, suggesting that odour can allow anticipation of
the type of food eaten and consequently the physiological oral changes necessary
to that ingestion. An interesting finding was that bread odour increased the
expression levels of several protein spots of immunoglobulin chains, which were
decreased by both bread or rice mastication. This may be of clinical relevance
since food olfactory stimulation of salivary immunoglobulins can be used to
potentiate the oral immune function of saliva. Moreover, the effects of bread
odour in the levels of salivary proteins, previously observed to be involved in
oral food processing led to the hypothesis of an influence of this odour in the
sensory perception of foods further ingested. Further studies are needed to
elucidate this point, as well as whether the changes observed for bread odour
are specific, or if different food odours lead to similar salivary proteome
responses. |
Is HbA1c an ideal biomarker of well-controlled diabetes? | No. The HbA1c is a biomarker with a central role in the diagnosis and follow-up of patients with diabetes mellitus, although not a perfect one. It is associated with high morbidity and mortality, and is not an ideal biomarker for assessment of well-controlled diabetes. | HbA1c is a biomarker with a central role in the diagnosis and follow-up of
patients with diabetes, although not a perfect one. Common comorbidities
encountered in patients with diabetes mellitus, such as renal insufficiency,
high output states (iron deficiency anaemia, haemolytic anaemia,
haemoglobinopathies and pregcy) and intake of specific drugs could compromise
the sensitivity and specificity of the biomarker. COVID-19 pandemic poses a
pressing challenge for the diabetic population, since maintaining optimal blood
glucose control is key to reduce morbidity and mortality rates. Alternative
methods for diabetes management, such as fructosamine, glycosylated albumin and
device-based continuous glucose monitoring, are discussed. |
Which tool has been developed for microRNA-target enrichment and network-based analysis? | MIENTURNET (MicroRNA ENrichment TURned NETwork) is a web tool that receives in input a list of miRNAs or mRNAs and tackles the problem of prioritizing miRNA-target interactions by performing a statistical analysis followed by a fully featured network-based visualization and analysis. The statistics is used to assess the significance of an over-representation of miRNA-target interactions and then MIENTURNET filters based on the statistical significance associated with each miRNA-target interaction. In addition, the holistic approach of the network theory is used to infer possible evidences of miRNA regulation by capturing emergent properties of the miRNA-target regulatory network that would be not evident through a pairwise analysis of the individual components. | |
List example genes that SWIM tool has identified and which are down-regulated in glioblastoma | SWIM is a software able to unveil a small pool of genes - called switch genes - critically associated with drastic changes in cell phenotype. Applying SWIM to the expression profiling of glioblastoma stem-like cells and conventional glioma cell lines identifies switch genes related to stem-like phenotype. SWIM identifies 171 switch genes that are all down-regulated in glioblastoma stem-like cells. This list encompasses genes like CAV1, COL5A1, COL6A3, FLNB, HMMR, ITGA3, ITGA5, MET, SDC1, THBS1, and VEGFC, involved in "ECM-receptor interaction" and "focal adhesion" pathways. | BACKGROUND: It is well-known that glioblastoma contains self-renewing, stem-like
subpopulation with the ability to sustain tumor growth. These cells - called
cancer stem-like cells - share certain phenotypic characteristics with
untransformed stem cells and are resistant to many conventional cancer
therapies, which might explain the limitations in curing human maligcies.
Thus, the identification of genes controlling the differentiation of these
stem-like cells is becoming a successful therapeutic strategy, owing to the
promise of novel targets for treating maligcies.
METHODS: Recently, we developed SWIM, a software able to unveil a small pool of
genes - called switch genes - critically associated with drastic changes in cell
phenotype. Here, we applied SWIM to the expression profiling of glioblastoma
stem-like cells and conventional glioma cell lines, in order to identify switch
genes related to stem-like phenotype.
RESULTS: SWIM identifies 171 switch genes that are all down-regulated in
glioblastoma stem-like cells. This list encompasses genes like CAV1, COL5A1,
COL6A3, FLNB, HMMR, ITGA3, ITGA5, MET, SDC1, THBS1, and VEGFC, involved in
"ECM-receptor interaction" and "focal adhesion" pathways. The inhibition of
switch genes highly correlates with the activation of genes related to neural
development and differentiation, such as the 4-core OLIG2, POU3F2, SALL2, SOX2,
whose induction has been shown to be sufficient to reprogram differentiated
glioblastoma into stem-like cells. Among switch genes, the transcription factor
FOSL1 appears as the brightest star since: it is down-regulated in stem-like
cells; it highly negatively correlates with the 4-core genes that are all
up-regulated in stem-like cells; the promoter regions of the 4-core genes harbor
a consensus binding motif for FOSL1.
CONCLUSIONS: We suggest that the inhibition of switch genes in stem-like cells
could induce the deregulation of cell communication pathways, contributing to
neoplastic progression and tumor invasiveness. Conversely, their activation
could restore the physiological equilibrium between cell adhesion and migration,
hampering the progression of cancer. Moreover, we posit FOSL1 as promising
candidate to orchestrate the differentiation of cancer stem-like cells by
repressing the 4-core genes' expression, which severely halts cancer growth and
might affect the therapeutic outcome. We suggest FOSL1 as novel putative
therapeutic and prognostic biomarker, worthy of further investigation. |
Describe SWItchMiner (SWIM) | SWItchMiner (SWIM) is a wizard-like software implementation of a procedure, previously described, able to extract information contained in complex networks. Specifically, SWIM allows unearthing the existence of a new class of hubs, called "fight-club hubs", characterized by a marked negative correlation with their first nearest neighbors. Among them, a special subset of genes, called "switch genes", appears to be characterized by an unusual pattern of intra- and inter-module connections that confers them a crucial topological role, interestingly mirrored by the evidence of their clinic-biological relevance. | SWItchMiner (SWIM) is a wizard-like software implementation of a procedure,
previously described, able to extract information contained in complex networks.
Specifically, SWIM allows unearthing the existence of a new class of hubs,
called "fight-club hubs", characterized by a marked negative correlation with
their first nearest neighbors. Among them, a special subset of genes, called
"switch genes", appears to be characterized by an unusual pattern of intra- and
inter-module connections that confers them a crucial topological role,
interestingly mirrored by the evidence of their clinic-biological relevance.
Here, we applied SWIM to a large panel of cancer datasets from The Cancer Genome
Atlas, in order to highlight switch genes that could be critically associated
with the drastic changes in the physiological state of cells or tissues induced
by the cancer development. We discovered that switch genes are found in all
cancers we studied and they encompass protein coding genes and non-coding RNAs,
recovering many known key cancer players but also many new potential biomarkers
not yet characterized in cancer context. Furthermore, SWIM is amenable to detect
switch genes in different organisms and cell conditions, with the potential to
uncover important players in biologically relevant scenarios, including but not
limited to human cancer. |
What promotes amyloid-peptide beta 42 (Aβ42) accumulation in neuroblastoma cells? | The apolipoprotein (apo) E4 isoform is the strongest risk factor for late-onset Alzheimer's disease (AD). ApoE4 is more susceptible to proteolysis than apoE2 and apoE3 isoforms and carboxyl-terminal truncated apoE4 forms have been found in AD patients' brain. A specific apoE4 fragment, apoE4-165, promotes amyloid-peptide beta 42 (Aβ42) accumulation in human neuroblastoma SK-N-SH cells and increased intracellular reactive oxygen species formation, two events considered to occur early in AD pathogenesis. | The apolipoprotein (apo) E4 isoform is the strongest risk factor for late-onset
Alzheimer's disease (AD). ApoE4 is more susceptible to proteolysis than apoE2
and apoE3 isoforms and carboxyl-terminal truncated apoE4 forms have been found
in AD patients' brain. We have previously shown that a specific apoE4 fragment,
apoE4-165, promotes amyloid-peptide beta 42 (Aβ42) accumulation in human
neuroblastoma SK-N-SH cells and increased intracellular reactive oxygen species
formation, two events considered to occur early in AD pathogenesis. Here, we
show that these effects are allele-dependent and absolutely require the apoE4
background. Furthermore, the exact length of the fragment is critical since
longer or shorter length carboxyl-terminal truncated apoE4 forms do not elicit
the same effects. Structural and thermodynamic analyses showed that apoE4-165
has a compact structure, in contrast to other carboxyl-terminal truncated apoE4
forms that are instead destabilized. Compared however to other allelic
backgrounds, apoE4-165 is structurally distinct and less thermodynamically
stable suggesting that the combination of a well-folded structure with
structural plasticity is a unique characteristic of this fragment. Overall, our
findings suggest that the ability of apoE fragments to promote Aβ42
intraneuronal accumulation is specific for both the apoE4 isoform and the
particular structural and thermodynamic properties of the fragment. |
Which method has been developed for detection of ATAC-seq or ChIP-seq signals with DNA methylation? | EpiMethylTag is a fast, low- input, low sequencing depth method that combines ATAC-seq or ChIP-seq (M-ATAC or M-ChIP) with bisulfite conversion, to simultaneously examine accessibility/TF binding and methylation on the same DNA. | Author information:
(1)New York University Langone Health, New York, NY, USA.
(2)New York Genome Center, New York, NY, USA.
(3)Meyer Cancer Center, Weill Cornell Medicine, New York, NY, USA.
(4)Laura and Isaac Perlmutter Cancer Center, NYU School of Medicine, New York,
NY, USA.
(5)Skirball Institute of Biomolecular Medicine, Department of Cell Biology,
Helen L. and Martin S. Kimmel Center for Biology and Medicine, Laura and Isaac
Perlmutter Cancer Center, New York, NY, USA.
(6)Sanford I. Weill Department of Medicine, Sandra and Edward Meyer Cancer
Center, Weill Cornell Medicine, New York, NY, USA.
(7)Institute of Computational Biomedicine, Weill Cornell Medicine, New York, NY,
USA.
(8)New York University Langone Health, New York, NY, USA.
[email protected].
(9)Skirball Institute of Biomolecular Medicine, Department of Cell Biology,
Helen L. and Martin S. Kimmel Center for Biology and Medicine, Laura and Isaac
Perlmutter Cancer Center, New York, NY, USA. [email protected]. |
Which protein is involved in the organization and regulation of pluripotency-associated three-dimensional enhancer networks? | KLF4 is involved in the organization and regulation of pluripotency-associated three-dimensional enhancer networks. | Author information:
(1)Sanford I Weill Department of Medicine, Sandra and Edward Meyer Cancer
Center, Weill Cornell Medicine, New York, NY, USA.
(2)Department of Pathology, NYU School of Medicine, New York, NY, USA.
(3)Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New
York, NY, USA.
(4)Weill-Cornell/Rockefeller/Sloan Kettering Tri-Institutional MD-PhD program,
New York, NY, USA.
(5)Department of Biochemistry, Sandra and Edward Meyer Cancer Center, Weill
Cornell Medical College, New York, NY, USA.
(6)Skirball Institute of Biomolecular Medicine, Department of Cell Biology and
Helen L. and Martin S. Kimmel Center for Biology and Medicine, NYU School of
Medicine, New York, NY, USA.
(7)Department of Pathology, NYU School of Medicine, New York, NY, USA.
[email protected].
(8)Laura and Isaac Perlmutter Cancer Center and Helen L. and Martin S. Kimmel
Center for Stem Cell Biology, NYU School of Medicine, New York, NY, USA.
[email protected].
(9)Applied Bioinformatics Laboratories, NYU School of Medicine, New York, NY,
USA. [email protected].
(10)Sanford I Weill Department of Medicine, Sandra and Edward Meyer Cancer
Center, Weill Cornell Medicine, New York, NY, USA. [email protected]. |
Where is the agouti-related peptide expressed? | Function. Agouti-related protein is expressed primarily in the adrenal gland, subthalamic nucleus, and hypothalamus, with lower levels of expression in the testis, kidneys, and lungs. | Energy metabolism and bone homeostasis share several neuronal regulatory
pathways. Within the ventral hypothalamus (VHT), the orexigenic neurons
co-express Agouti-related peptide (AgRP) and neuropeptide Y (NPY) and the
anorexigenic neurons co-express, α-melanocyte stimulating hormone derived from
proopiomelanocortin (POMC), and cocaine and amphetamine-regulated transcript
(CART). These neurons regulate both processes, yet their relative contribution
is unknown. Previously, using genetically targeted activator protein (AP1)
alterations as a tool, we showed in adult mice that AgRP or POMC neurons are
capable of inducing whole-body energy catabolism and bone accrual, with
different effects on bone resorption. Here, we investigated whether co-residing
neurons exert similar regulatory effects. We show that AP1 antagonists targeted
to NPY-producing or CART-producing neurons in adult mice stimulate energy
expenditure, reduce body weight gain and adiposity and promote trabecular bone
formation and mass, yet again via different effects on bone resorption, as
measured by serum level of carboxy-terminal collagen type I crosslinks (CTX). In
addition, AP1 antagonists promote neurite expansion, increasing neurite number,
length, and surface area in primary hypothalamic neuronal cultures. Overall, our
data demonstrate that the orexigenic NPY and anorexigenic CART neurons both have
the capacity to stimulate energy burning state and increase bone mass. © 2020
American Society for Bone and Mineral Research. |
What is the function of ketohexokinase-A? | The central fructose-metabolising enzyme is ketohexokinase (KHK), which exists in two isoforms: KHK-A and KHK-C. | Fructose is a major component of dietary sugar and its overconsumption
exacerbates key pathological features of metabolic syndrome. The central
fructose-metabolising enzyme is ketohexokinase (KHK), which exists in two
isoforms: KHK-A and KHK-C, generated through mutually exclusive alternative
splicing of KHK pre-mRNAs. KHK-C displays superior affinity for fructose
compared with KHK-A and is produced primarily in the liver, thus restricting
fructose metabolism almost exclusively to this organ. Here we show that
myocardial hypoxia actuates fructose metabolism in human and mouse models of
pathological cardiac hypertrophy through hypoxia-inducible factor 1α (HIF1α)
activation of SF3B1 and SF3B1-mediated splice switching of KHK-A to KHK-C.
Heart-specific depletion of SF3B1 or genetic ablation of Khk, but not Khk-A
alone, in mice, suppresses pathological stress-induced fructose metabolism,
growth and contractile dysfunction, thus defining signalling components and
molecular underpinnings of a fructose metabolism regulatory system crucial for
pathological growth. Dietary fructose is primarily metabolized in the liver. Here we demonstrate
that, compared with normal hepatocytes, hepatocellular carcinoma (HCC) cells
markedly reduce the rate of fructose metabolism and the level of reactive oxygen
species, as a result of a c-Myc-dependent and heterogeneous nuclear
ribonucleoprotein (hnRNP) H1- and H2-mediated switch from expression of the
high-activity fructokinase (KHK)-C to the low-activity KHK-A isoform.
Importantly, KHK-A acts as a protein kinase, phosphorylating and activating
phosphoribosyl pyrophosphate synthetase 1 (PRPS1) to promote pentose phosphate
pathway-dependent de novo nucleic acid synthesis and HCC formation. Furthermore,
c-Myc, hnRNPH1/2 and KHK-A expression levels and PRPS1 Thr225 phosphorylation
levels correlate with each other in HCC specimens and are associated with poor
prognosis for HCC. These findings reveal a pivotal mechanism underlying the
distinct fructose metabolism between HCC cells and normal hepatocytes and
highlight the instrumental role of KHK-A protein kinase activity in promoting de
novo nucleic acid synthesis and HCC development. Background: The identification of prognostic markers for non-small-cell lung
carcinoma (NSCLC) is needed for clinical practice. The metabolism-reprogramming
marker ketohexokinase (KHK)-A and acetyl-CoA synthetase 2 (ACSS2)
phosphorylation at S659 (ACSS2 pS659) play important roles in tumorigenesis and
tumor development. However, the clinical significance of KHK-A and ACSS2 pS659
in NSCLC is largely unknown. Methods: The expression levels of KHK-A and ACSS2
pS659 were assessed by immunohistochemistry analyses of surgical specimens from
303 NSCLC patients. The prognostic values of KHK-A and ACSS2 pS659 were
evaluated by Kaplan-Meier methods and Cox regression models. Results: The
expression levels of KHK-A and ACSS2 pS659 were significantly higher in NSCLC
tissues than those in adjacent non-tumor tissues (P < 0.0001). KHK-A or ACSS2
pS659 alone and the combination of KHK-A and ACSS2 pS659 were inversely
correlated with overall survival in NSCLC patients (P < 0.001). The multivariate
analysis indicated that KHK-A or ACSS2 pS659 and KHK-A/ACSS2 pS659 were
independent prognostic biomarkers for NSCLC (P = 0.008 for KHK-A, P < 0.001 for
ACSS2 pS659, and P < 0.001 for KHK-A/ACSS2 pS659). Furthermore, the combination
of KHK-A and ACSS2 pS659 can be used as a prognostic indicator for all stages of
NSCLC. Conclusions: KHK-A or ACSS2 pS659 alone and the combination of KHK-A and
ACSS2 pS659 can be used as prognostic markers for NSCLC. Our findings highlight
the important role of metabolic reprogramming in NSCLC progression. |
Are the major royal jelly proteins similar to the yellow proteins? | Yes,
Major royal jelly proteins (named MRJP1-5) of honeybee (Apis mellifera), yellow proteins of Drosophila, together with putative proteins found in several bacteria, form a protein family termed the MRJP/yellow family. | The yellow locus in Drosophila is involved in both cuticle development and
behaviour. However, the function of the encoded protein is unknown. Here we have
characterised the sequence and expression pattern of a new Drosophila gene,
designated yellow-B, encoding a 453-amino-acid protein that is 57% identical to
Yellow. High levels of yellow-B mRNA are present in the larval-pupal stages, but
the gene is also expressed in the head. Bioinformatics analysis indicates that
the Drosophila genome encodes at least 7 members of the Yellow family
distributed among chromosomes 2, 3, and X. The Yellow proteins are related to
the Royal Jelly proteins and have no relatives in other non-insect metazoan
species. Interestingly, a Yellow-like protein is encoded by the genome of a
radiation tolerant bacterium, Deinococcus radiodurans. |
Which R packages have been developed for studying TADs? | TADCompare is an R Package for differential and temporal analysis of Topologically Associated Domains. SpectralTAD is an R package for defining a hierarchy of topologically associated domains using spectral clustering. | BACKGROUND: The three-dimensional (3D) structure of the genome plays a crucial
role in gene expression regulation. Chromatin conformation capture technologies
(Hi-C) have revealed that the genome is organized in a hierarchy of
topologically associated domains (TADs), sub-TADs, and chromatin loops.
Identifying such hierarchical structures is a critical step in understanding
genome regulation. Existing tools for TAD calling are frequently sensitive to
biases in Hi-C data, depend on tunable parameters, and are computationally
inefficient.
METHODS: To address these challenges, we developed a novel sliding window-based
spectral clustering framework that uses gaps between consecutive eigenvectors
for TAD boundary identification.
RESULTS: Our method, implemented in an R package, SpectralTAD, detects
hierarchical, biologically relevant TADs, has automatic parameter selection, is
robust to sequencing depth, resolution, and sparsity of Hi-C data. SpectralTAD
outperforms four state-of-the-art TAD callers in simulated and experimental
settings. We demonstrate that TAD boundaries shared among multiple levels of the
TAD hierarchy were more enriched in classical boundary marks and more conserved
across cell lines and tissues. In contrast, boundaries of TADs that cannot be
split into sub-TADs showed less enrichment and conservation, suggesting their
more dynamic role in genome regulation.
CONCLUSION: SpectralTAD is available on Bioconductor,
http://bioconductor.org/packages/SpectralTAD/ . |
Which bioconductor tool has been developed for accessing bacterial regulatory networks? | The Regutools R package to facilitates programmatic access to RegulonDB data in computational biology. regutools gives researchers the possibility of writing reproducible workflows with automated queries to RegulonDB. The regutools package serves as a bridge between RegulonDB data and the Bioconductor ecosystem by reusing the data structures and statistical methods powered by other Bioconductor packages. | SUMMARY: RegulonDB has collected, harmonized and centralized data from hundreds
of experiments for nearly two decades and is considered a point of reference for
transcriptional regulation in Escherichia coli K12. Here, we present the
regutools R package to facilitate programmatic access to RegulonDB data in
computational biology. regutools gives researchers the possibility of writing
reproducible workflows with automated queries to RegulonDB. The regutools
package serves as a bridge between RegulonDB data and the Bioconductor ecosystem
by reusing the data structures and statistical methods powered by other
Bioconductor packages. We demonstrate the integration of regutools with
Bioconductor by analyzing transcription factor DNA binding sites and
transcriptional regulatory networks from RegulonDB. We anticipate that regutools
will serve as a useful building block in our progress to further our
understanding of gene regulatory networks.
AVAILABILITY AND IMPLEMENTATION: regutools is an R package available through
Bioconductor at bioconductor.org/packages/regutools. |
Is the Apis mellifera genome available? | Yes,
the Apis mellifera genome is available since 2006. | Phenotypic plasticity, the ability of an organism to alter its phenotype in
response to an environmental cue, facilitates rapid adaptation to changing
environments. Plastic changes in morphology and behavior are underpinned by
widespread gene expression changes. However, it is unknown if, or how, genomes
are structured to ensure these robust responses. Here, we use repression of
honeybee worker ovaries as a model of plasticity. We show that the honeybee
genome is structured with respect to plasticity; genes that respond to an
environmental trigger are colocated in the honeybee genome in a series of gene
clusters, many of which have been assembled in the last 80 My during the
evolution of the Apidae. These clusters are marked by histone modifications that
prefigure the gene expression changes that occur as the ovary activates,
suggesting that these genomic regions are poised to respond plastically. That
the linear sequence of the honeybee genome is organized to coordinate widespread
gene expression changes in response to environmental influences and that the
chromatin organization in these regions is prefigured to respond to these
influences is perhaps unexpected and has implications for other examples of
plasticity in physiology, evolution, and human disease. Honey bee research is believed to be influenced dramatically by colony collapse
disorder (CCD) and the sequenced genome release in 2006, but this assertion has
never been tested. By employing text-mining approaches, research trends were
tested by analyzing over 14,000 publications during the period of 1957 to 2017.
Quantitatively, the data revealed an exponential growth until 2010 when the
number of articles published per year ceased following the trend. Analysis of
author-assigned keywords revealed that changes in keywords occurred roughly
every decade with the most fundamental change in 1991-1992, instead of 2006.
This change might be due to several factors including the research
intensification on the Varroa mite. The genome release and CCD had quantitively
only minor effects, mainly on honey bee health-related topics post-2006. Further
analysis revealed that computational topic modeling can provide potentially
hidden information and connections between some topics that might be ignored in
author-assigned keywords. Honey bees are large-scale monitoring tools due to their extensive environmental
exploration. In their activities and from the hive ecosystem complex, they get
in close contact with many organisms whose traces can be transferred into the
honey, which can represent an interesting reservoir of environmental DNA (eDNA)
signatures and information useful to analyse the honey bee hologenome
complexity. In this study, we tested a deep shotgun sequencing approach of honey
DNA coupled with a specifically adapted bioinformatic pipeline. This methodology
was applied to a few honey samples pointing out DNA sequences from 191 organisms
spanning different kingdoms or phyla (viruses, bacteria, plants, fungi,
protozoans, arthropods, mammals). Bacteria included the largest number of
species. These multi-kingdom signatures listed common hive and honey bee gut
microorganisms, honey bee pathogens, parasites and pests, which resembled a
complex interplay that might provide a general picture of the honey bee
pathosphere. Based on the Apis mellifera filamentous virus genome diversity (the
most abundant detected DNA source) we obtained information that could define the
origin of the honey at the apiary level. Mining Apis mellifera sequences made it
possible to identify the honey bee subspecies both at the mitochondrial and
nuclear genome levels. |
What genes is implicated in myotonic goats and other nondystrophic myotonias? | The gene encoding clcn1, mBNl1, gcic-1, scn4a, clc-1 and dmpk are implicated in myotonic goats and other nondystrophic myotonias. | Certain forms of myotonia, a condition characterized by delayed relaxation of
muscle secondary to sarcolemmal hyperexcitability, are caused by diminished
chloride conductance in the muscle cell membrane. We have investigated the
molecular basis for decreased muscle chloride conductance in the myotonic goat,
an historically important animal model for the elucidation of the role of
chloride in muscle excitation. A single nucleotide change causing the
substitution of proline for a conserved alanine residue in the carboxyl terminus
of the goat muscle chloride channel (gCIC-1) was discovered. Heterologous
expression of the mutation demonstrated a substantial (+47 mV) shift in the
midpoint of steady-state activation of the channel, resulting in a diminished
channel open probability at voltages near the resting membrane potential of
skeletal muscle. These results provide a molecular basis for the decreased
chloride conductance in myotonic muscle. Mutations in the skeletal muscle voltage-gated sodium channel alpha-subunit gene
(SCN4A) have been associated with a spectrum of inherited nondystrophic
myotonias and periodic paralyses. Most disease-associated SCN4A alleles occur in
portions of the gene that encode the third and fourth repeat domains with the
conspicuous absence of mutations in domain 1. Here we describe a family
segregating an unusual autosomal domit congenital myotonia associated with
debilitating pain especially severe in the intercostal muscles. A novel SCN4A
mutation causing the replacement of Val445 in the sixth transmembrane segment of
domain 1 with methionine was discovered in all affected individuals and is the
likely genetic basis for the syndrome. Myotonia was resistant to treatment;
however, the most severely affected family member responded dramatically to the
sodium channel blocking agent flecainide. A 7-month-old New Forest foal presented for episodes of recumbency and stiffness
with myotonic discharges on electromyography. The observed phenotype resembled
congenital myotonia caused by CLCN1 mutations in goats and humans. Mutation of
the CLCN1 gene was considered as possible cause and mutation analysis was
performed. The affected foal was homozygous for a missense mutation (c.1775A>C,
p.D592A) located in a well conserved domain of the CLCN1 gene. The mutation
showed a recessive mode of inheritance within the reported pony family.
Therefore, this CLCN1 polymorphism is considered to be a possible cause of
congenital myotonia. Thomsen's and Becker's diseases are the most prevalent nondystrophic myotonias.
Their frequency varies, according to different sources, from 1 : 100 000 to 1 :
10 000. Thomsen's myotonia is autosomal domit, and Becker's myotonia is
autosomal recessive. Both diseases result from mutations of the CLCN1 gene
encoding chloride ion channels of skeletal muscles. Molecular genetic analysis
of the CLCN1 gene has been performed in patients with diagnoses of nondystrophic
Thomsen's and Becker's myotonias living in the Russian Federation. A sample of
79 unrelated probands with nondystrophic Thomsen's and Becker's myotonias and 44
their relatives has been formed in the Laboratory of DNA Diagnosis of the
Medical Genetic Research Center of the Russian Academy of Medical Sciences.
Forty CLCN1 gene mutations have been found in a total of 118 chromosomes of 66
probands, including 21 familial and 45 sporadic cases. About half the mutations
detected (45%) have been found for the first time; they are not described in the
SNP database (ncbi.nlm.nih.gov). The following mutations (substitutions) have
been detected in more than one chromosome, accounting for a total of 59.3% of
chromosomes with mutations: Glyl90Ser (5.9%), c.1437-1450del14 (9.3%), Ala493Glu
(5.1%), Thr550Met (3.4%), Tyr686Stop (5.1%), and Arg894Stop (30.5%). Author information:
(1)CHU Saint-Etienne, Hôpital Nord, Department of Neurology, Saint-Etienne
F-42055, France; Rhône-Alpes Reference Center for Rare Neuromuscular Diseases,
Saint-Etienne F-42055, France. Electronic address:
[email protected].
(2)Assistance Publique-Hôpitaux de Paris, National Reference Center for
Neuromuscular Channelopathies, Hôpital Pitié-Salpêtrière, Paris 75013, France.
(3)CHU Saint-Etienne, Hôpital Nord, Department of Neurology, Saint-Etienne
F-42055, France; Rhône-Alpes Reference Center for Rare Neuromuscular Diseases,
Saint-Etienne F-42055, France.
(4)Assistance Publique-Hôpitaux de Paris, National Reference Center for
Neuromuscular Channelopathies, Hôpital Pitié-Salpêtrière, Paris 75013, France;
Université Pierre et Marie Curie-Paris VI, Department of Physiology, 75005
Paris, France; CNRS-INSERM-UPMC UMR 1127-7225, Institut Cerveau Moelle, Hôpital
Pitié-Salpêtrière, Paris 75013, France.
(5)Rhône-Alpes Reference Center for Rare Neuromuscular Diseases, Saint-Etienne
F-42055, France; CHU Saint-Etienne, Hôpital Bellevue, Department of Paediatric
Physical Medicine and Rehabilitation, Saint-Etienne F-42055, France.
(6)UMR Inserm U930, Université François Rabelais de Tours. CHRU de Tours,
Service "Neuropédiatrie et Handicaps", Tours 37044, France.
(7)Rhône-Alpes Reference Center for Rare Neuromuscular Diseases, Saint-Etienne
F-42055, France; CHU Saint-Etienne, Hôpital Nord, Paediatric Intensive Care
Unit, Saint-Etienne F-42055, France.
(8)Assistance Publique-Hôpitaux de Paris, National Reference Center for
Neuromuscular Channelopathies, Hôpital Pitié-Salpêtrière, Paris 75013, France;
CNRS-INSERM-UPMC UMR 1127-7225, Institut Cerveau Moelle, Hôpital
Pitié-Salpêtrière, Paris 75013, France; Assistance Publique-Hôpitaux de Paris,
Service de Biochimie Métabolique, Centre de Génétique, Groupe Hospitalier
Pitié-Salpêtrière Charles Foix, Paris 75013, France.
(9)Rhône-Alpes Reference Center for Rare Neuromuscular Diseases, Saint-Etienne
F-42055, France; CHU Saint-Etienne, Hôpital Nord, Department of Genetics,
Saint-Etienne F-42055, France.
(10)Assistance Publique-Hôpitaux de Paris, National Reference Center for
Neuromuscular Channelopathies, Hôpital Pitié-Salpêtrière, Paris 75013, France;
CNRS-INSERM-UPMC UMR 1127-7225, Institut Cerveau Moelle, Hôpital
Pitié-Salpêtrière, Paris 75013, France. Thomsen's (TM) and Becker's (BM) Myotonias are nondystrophic myotonias. At
present, 150 mutations in the CLCN1 gene, which results in the development of TM
and BM, have been described. c.2680C > T (p.Arg894*) is the most common
mutation. In the Northern Scandinavian countries, the population frequency of
this mutation is 0.87%, while in the Russian Federation, it is equal to 1.2%
(this study). Based on the results of a molecular-genetic analysis of CLCN1 gene
in patients with nondystrophic myotonias, the calculated frequency of TM and BM
in Russia is 1:8165 and 1:710, respectively. We have conducted haplotype
analysis using microsatellite markers and intragene SNP, which has shown that
the prevalence of p.Arg894* mutation in Russia results from the founder effect,
and the time of its scattering is 3680 ± 1240 years. Mutations in the gene coding for the skeletal muscle Cl(-) channel (CLCN1) lead
to domit or recessive myotonia. Here, we identified and characterized CLCN1
mutations in Costa Rican patients, who had been clinically diagnosed with
myotonic dystrophy type 1 but who were negative for DM1 mutations. CLCN1
mutations c.501C>G, p.F167L and c.1235A>C, p.Q412P appeared to have recessive
inheritance but patients had atypical clinical phenotypes; c.313C>T, p.R105C was
found in combination with c.501C>G, p.F167L in an apparently recessive family
and the c.461A>G, p.Q154R variant was associated with a less clear clinical
picture. In Xenopus oocytes, none of the mutations exhibited alterations of fast
or slow gating parameters or single channel conductance, and mutations p.R105C,
p.Q154R, and p.F167L were indistinguishable from wild-type (WT). p.Q412P
displayed a dramatically reduced current density, surface expression and exerted
no domit negative effect in the context of the homodimeric channel.
Fluorescently tagged constructs revealed that p.Q412P is expressed
inefficiently. Our study confirms p.F167L and p.R105C as myotonia mutations in
the Costa Rican population, whereas p.Q154R may be a benign variant. p.Q412P
most likely induces a severe folding defect, explaining the lack of domice in
patients and expression systems, but has WT properties once expressed in the
plasma membrane. Myotonia congenita (MC), paramyotonia congenita (PC) and sodium channel
myotonias(SCM) were belonged to Non-dystrophic myotonias, in which muscle
relaxation is delayed after voluntary or evoked contraction. These diseases can
not be simply distinguished only based on symptoms and signs but also on
genetics: more than 100 mutations in the CLCN1 gene have been associated with
MC, while at least 20 mutations in the SCN4A gene have been associated with PC
and SCM. Most of these genetics studies have been conducted outside China, only
several MC, PC, and SCM families accepted gene scan were reported in China.
Therefore we analyzed genetic mutations in CLCN1 and SCN4A in 10 Chinese
families clinically diagnosed with Non-dystrophic myotonias. Our result revealed
12 potential disease-causing mutations(3 mutations were novel) that were present
in the probands and affected family members. We also reviewed all available
literature on mutations linked to these 3 disease in Chinese populations. Our
results may help identify genetic determits as well as clarify
genotype-phenotype relationships. Nondystrophic myotonias are disorders of Na+ (Nav1.4 or SCN4A) and Cl- (CLCN1)
channels in skeletal muscles, and frequently show phenotype heterogeneity. The
molecular mechanism underlying their pathophysiology and phenotype heterogeneity
remains unclear. As zebrafish models have been recently exploited for studies of
the pathophysiology and phenotype heterogeneity of various human genetic
diseases, a zebrafish model may be useful for delineating nondystrophic
myotonias. Here, we generated transgenic zebrafish expressing a human mutant
allele of SCN4A, referred to as Tg(mylpfa:N440K), and needle electromyography
revealed increased number of myotonic discharges and positive sharp waves in the
muscles of Tg(mylpfa:N440K) than in controls. In addition, forced exercise test
at a water temperature of 24 °C showed a decrease in the distance moved, time
spent in and number of visits to the zone with stronger swimming resistance.
Finally, a forced exercise test at a water temperature of 18 °C exhibited a
higher number of dive-bombing periods and drifting-down behavior than in
controls. These findings indicate that Tg(mylpfa:N440K) is a good vertebrate
model of exercise- and cold-induced human nondystrophic myotonias. This
zebrafish model may contribute to provide insight into the pathophysiology of
myotonia in sodium channelopathy and could be used to explore a new therapeutic
avenue. INTRODUCTION: Mutations of the voltage-gated sodium channel gene (SCN4A), which
encodes Nav1.4, cause nondystrophic myotonia that occasionally is associated
with severe apnea and laryngospasm. There are case reports of nondystrophic
myotonia due to mutations in the C-terminal tail (CTerm) of Nav1.4, but the
functional analysis is scarce.
METHODS: We present two families with nondystrophic myotonia harboring a novel
heterozygous mutation (E1702del) and a known heterozygous mutation (E1702K).
RESULTS: The proband with E1702K exhibited repeated rhabdomyolysis, and the
daughter showed laryngospasm and cyanosis. Functional analysis of the two
mutations as well as another known heterozygous mutation (T1700_E1703del), all
located on EF hand-like motif in CTerm, was conducted with whole-cell recording
of heterologously expressed channel. All mutations displayed impaired fast
inactivation.
DISCUSSION: The CTerm of Nav1.4 is vital for regulating fast inactivation. The
study highlights the importance of accumulating pathological mutations of Nav1.4
and their functional analysis data. Author information:
(1)Department of Neurology, Radboud University Medical Center, Nijmegen, the
Netherlands.
(2)Department of Neurology, Ohio State University Wexner Medical Center,
Columbus, Ohio.
(3)Department of Neurology, University of Kansas Medical Center, Kansas City,
Kansas.
(4)Department of Physiology, David Geffen School of Medicine, University of
California, Los Angeles, Los Angeles, California.
(5)Assistance Publique-Hôpitaix de Paris, Sorbonne Université, INSERM, Service
of Neuro-Myology and UMR 974, Institute of Myology, University Hospital
Pitié-Salpêtrière, Paris, France.
(6)Department of Neurology, University of Rochester, Rochester, New York.
(7)MRC Centre for Neuromuscular Diseases, Department of Neuromuscular diseases,
UCL Queen Square Institute of Neurology, United Kingdom.
(8)Department of Neurorehabilitation Sciences, Casa Cura Policlinico, Milan,
Italy.
(9)Department of Biomedical Sciences for Health, University of Milan, Milan,
Italy.
(10)Neurorehabilitation Unit, University of Milan, NEuroMuscular Omnicentre
(NEMO), Fondazione Serena Onlus, Milan, Italy.
(11)Department of Neurology and Neurotherapeutics, UT Southwestern Medical
Center, Dallas, Texas. |
Has the olive tree pollen proteome been studied? | Yes,
Olive pollen is a major allergenic source worldwide due to its extensive cultivation. We have combined available genomics data with a comprehensive proteomics approach to get the annotated olive tree (Olea europaea L.) pollen proteome and define its complex allergenome. | |
Is cadherin a plasma membrane marker? | Yes,
cadherin is a plasma membrane protein marker. | AIMS: Hepatocyte growth factor-regulated tyrosine kinase substrate (Hgs), a key
component of the endosomal sorting complex required for transport (ESCRT), has
been implicated in many essential biological processes. However, the
physiological role of endogenous Hgs in the vascular system has not previously
been explored. Here, we have generated brain endothelial cell (EC) specific Hgs
knockout mice to uncover the function of Hgs in EC polarity and cerebrovascular
stability.
METHODS AND RESULTS: Knockout of Hgs in brain ECs led to impaired endothelial
apicobasal polarity and brain vessel collapse in mice. We determined that Hgs is
essential for recycling of vascular endothelial (VE)-cadherin to the plasma
membrane, since loss of Hgs blocked trafficking of endocytosed VE-cadherin from
early endosomes to recycling endosomes, and impaired the motility of recycling
endosomes. Supportively, overexpression of the motor kinesin family member 13A
(KIF13A) restored endosomal recycling and rescued abrogated polarized
trafficking and distribution of VE-cadherin in Hgs knockdown ECs.
CONCLUSION: These data uncover a novel physiological function of Hgs and support
an essential role for the ESCRT machinery in the maintece of EC polarity and
cerebrovascular stability. The epithelial-to-mesenchymal transition is a highly dynamic cell process and
tools such as fluorescence recovery after photobleaching (FRAP), which allow the
study of rapid protein dynamics, enable the following of this process in vivo.
This technique uses a short intense pulse of photons to disrupt the fluorescence
of a tagged protein in a region of a sample. The fluorescent signal intensity
after this bleaching is then recorded and the signal recovery used to provide an
indicator of the dynamics of the protein of interest. This technique can be
applied to any fluorescently tagged protein, but membrane-bound proteins present
an interesting challenge as they are spatially confined and subject to
specialized cellular trafficking. Several methods of analysis can be applied
which can disentangle these various processes and enable the extraction of
information from the recovery curves. Here we describe this technique when
applied to the quantification of the plasma membrane-bound E-cadherin protein in
vivo using the epidermis of the late embryo of Drosophila melanogaster
(Drosophila) as an example of this technique. |
What impacts stability of genomic imprinting in mouse pluripotent stem cells? | A susceptibility locus on chromosome 13 profoundly impacts the stability of genomic imprinting in mouse pluripotent stem cells. | Author information:
(1)Skirball Institute of Biomolecular Medicine, Department of Cell Biology, NYU
Langone Medical Center, New York, NY 10016, USA; Helen L. and Martin S. Kimmel
Center for Biology and Medicine, NYU Langone Medical Center, New York, NY 10016,
USA; Laura and Isaac Perlmutter Cancer Center, NYU Langone Medical Center, New
York, NY 10016, USA; Sanford I. Weill Department of Medicine, Sandra and Edward
Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA.
(2)Skirball Institute of Biomolecular Medicine, Department of Cell Biology, NYU
Langone Medical Center, New York, NY 10016, USA; Helen L. and Martin S. Kimmel
Center for Biology and Medicine, NYU Langone Medical Center, New York, NY 10016,
USA; Department of Biochemistry and Molecular Pharmacology, NYU Langone Medical
Center, New York, NY 10016, USA.
(3)Sanford I. Weill Department of Medicine, Sandra and Edward Meyer Cancer
Center, Weill Cornell Medicine, New York, NY 10021, USA.
(4)Skirball Institute of Biomolecular Medicine, Department of Cell Biology, NYU
Langone Medical Center, New York, NY 10016, USA; Helen L. and Martin S. Kimmel
Center for Biology and Medicine, NYU Langone Medical Center, New York, NY 10016,
USA; Department of Biochemistry and Molecular Pharmacology, NYU Langone Medical
Center, New York, NY 10016, USA; Department of Biology, New York University, New
York, NY 10003, USA.
(5)Skirball Institute of Biomolecular Medicine, Department of Cell Biology, NYU
Langone Medical Center, New York, NY 10016, USA; Helen L. and Martin S. Kimmel
Center for Biology and Medicine, NYU Langone Medical Center, New York, NY 10016,
USA; Laura and Isaac Perlmutter Cancer Center, NYU Langone Medical Center, New
York, NY 10016, USA; Sanford I. Weill Department of Medicine, Sandra and Edward
Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA. Electronic
address: [email protected]. |
What are the end products of the shikimate pathway? | The shikimate pathway responsible for the generation of aromatic amino acids | The most common route to produce aromatic chemicals - organic compounds
containing at least one benzene ring in their structure - is chemical synthesis.
These processes, usually starting from an extracted fossil oil molecule such as
benzene, toluene, or xylene, are highly environmentally unfriendly due to the
use of non-renewable raw materials, high energy consumption and the usual
production of toxic by-products. An alternative way to produce aromatic
compounds is extraction from plants. These extractions typically have a low
yield and a high purification cost. This motivates the search for alternative
platforms to produce aromatic compounds through low-cost and environmentally
friendly processes. Microorganisms are able to synthesize aromatic amino acids
through the shikimate pathway. The construction of microbial cell factories able
to produce the desired molecule from renewable feedstock becomes a promising
alternative. This review article focuses on the recent advances in microbial
production of aromatic products, with a special emphasis on metabolic
engineering strategies, as well as bioprocess optimization. The recent
combination of these two techniques has resulted in the development of several
alternative processes to produce phenylpropanoids, aromatic alcohols, phenolic
aldehydes, and others. Chemical species that were unavailable for human
consumption due to the high cost and/or high environmental impact of their
production, have now become accessible. Allosteric regulation is important in many biological processes, including cell
signaling, gene regulation, and metabolism. Saccharomyces cerevisiae chorismate
mutase (ScCM) is a key homodimeric enzyme in the shikimate pathway responsible
for the generation of aromatic amino acids, where it is allosterically inhibited
and activated by Tyr and Trp, respectively. Our previous studies indicated that
binding of both allosteric effectors is negatively cooperative, that is binding
at one allosteric binding site discourages binding at the other, due to the
entropic penalty of binding the second allosteric effector. We utilized variable
temperature isothermal titration calorimetry (ITC) and nuclear magnetic
resoce (NMR) experiments to better understand the entropic contributions to
allosteric effector binding, including changes to solvent entropy and protein
conformational entropy. Upon binding either Tyr or Trp, ScCM experiences a
quenching of motions on the picosecond-to-osecond time scale, which we could
relate to a loss of protein conformational entropy. Further ITC and NMR studies
were consistent with the Tyr-bound form of ScCM being associated with more water
molecules compared to the Trp-bound form and Tyr binding being associated with a
less positive solvent entropy change. These studies provide insight into the
role of structural dynamics in ScCM function and highlight the importance of
solvent entropy changes in allosteric regulation, a historically
underappreciated concept. Author information:
(1)Frontier Science Center for Synthetic Biology and Key Laboratory of Systems
Bioengineering (Ministry of Education); SynBio Research Platform, Collaborative
Innovation Center of Chemical Science and Engineering, School of Chemical
Engineering and Technology, Tianjin University, Tianjin, 300072, China.
(2)Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of
Sciences, Tianjin, 300308, China.
(3)Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences,
Tianjin, 300308, China.
(4)University of Chinese Academy of Sciences, Beijing, 100049, China.
(5)Frontier Science Center for Synthetic Biology and Key Laboratory of Systems
Bioengineering (Ministry of Education); SynBio Research Platform, Collaborative
Innovation Center of Chemical Science and Engineering, School of Chemical
Engineering and Technology, Tianjin University, Tianjin, 300072, China.
[email protected].
(6)Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of
Sciences, Tianjin, 300308, China. [email protected].
(7)Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences,
Tianjin, 300308, China. [email protected].
(8)University of Chinese Academy of Sciences, Beijing, 100049, China.
[email protected]. |
What are the uber-operons? | Uber-operons are groups of functionally or transcriptionally related operons, whose gene sets are conserved across multiple reference genomes. Many of the uber-operons correspond to parts of known regulons or biological pathways or are involved in highly related biological processes based on their Gene Ontology (GO) assignments. | We present a study on computational identification of uber-operons in a
prokaryotic genome, each of which represents a group of operons that are
evolutionarily or functionally associated through operons in other (reference)
genomes. Uber-operons represent a rich set of footprints of operon evolution,
whose full utilization could lead to new and more powerful tools for elucidation
of biological pathways and networks than what operons have provided, and a
better understanding of prokaryotic genome structures and evolution. Our
prediction algorithm predicts uber-operons through identifying groups of
functionally or transcriptionally related operons, whose gene sets are conserved
across the target and multiple reference genomes. Using this algorithm, we have
predicted uber-operons for each of a group of 91 genomes, using the other 90
genomes as references. In particular, we predicted 158 uber-operons in
Escherichia coli K12 covering 1830 genes, and found that many of the
uber-operons correspond to parts of known regulons or biological pathways or are
involved in highly related biological processes based on their Gene Ontology
(GO) assignments. For some of the predicted uber-operons that are not parts of
known regulons or pathways, our analyses indicate that their genes are highly
likely to work together in the same biological processes, suggesting the
possibility of new regulons and pathways. We believe that our uber-operon
prediction provides a highly useful capability and a rich information source for
elucidation of complex biological processes, such as pathways in microbes. All
the prediction results are available at our Uber-Operon Database:
http://csbl.bmb.uga.edu/uber, the first of its kind. |
Which key gene is involved in syndromic obesity phenotype of patients with 1p21.3 microdeletions? | MIR137 is the key gene mediator of the syndromic obesity phenotype of patients with 1p21. 3 microdeletions. | BACKGROUND: Deletions in the long arm of chromosome 1 have been described in
patients with a phenotype consisting primarily of obesity, intellectual
disability and autism-spectrum disorder. The minimal region of overlap comprises
two genes: DPYD and MIR137.
CASE PRESENTATION: We describe a 10-year-old boy with syndromic obesity who
carries a novel 1p21.3 deletion overlapping the critical region with the MIR137
gene only.
CONCLUSIONS: This study suggests that MIR137 is the mediator of the obesity
phenotype of patients carrying 1p21.3 microdeletions. |
Is cabergoline used for treatment of the Nelson's syndrome ? | Yes, cabergoline has been shown to be effective for treatment of the Nelson's syndrome. | A woman affected by Cushing's disease underwent bilateral adrenalectomy followed
by radiotherapy of the hypothalamic-pituitary area when she was 18 years old.
Thereafter, she used hydrocortisone acetate replacement therapy (35.5 mg divided
into two daily doses). At the age of 26 years, the patient exhibited the
clinical signs of the Nelson's syndrome, i.e. skin and gingival
hyperpigmentation accompanied by amenorrhea, and elevated ACTH plasma levels
(2,850 pg/ml, normal range 15-80 pg/ml). The magnetic resoce imaging (MRI)
analysis of the sellar region evidenced a pituitary macroadenoma, measuring 14 x
13 mm. The patient was initially treated with cyproheptadine hydrochloride (12
mg/day) for 18 months. There was a partial improvement of the symptoms, with a
reduction of the ACTH plasma levels to 112 pg/ml, but without any modification
of the tumor mass. Due to sleepiness and weight gain, the cyproheptadine
treatment was interrupted and substituted by a cabergoline (0.5 mg twice a week)
therapy. Soon after cabergoline was applied an improvement of the clinical
symptoms and signs was observed such as a regression of the tumor mass and the
normalization of the ACTH plasma titers (38 pg/ml). Later, cabergoline was
substituted by bromocriptine (7.5 mg/day) and the plasma levels of ACTH
increased again (247 pg/ml), and headache and cutaneous hyperpigmentation were
recorded. When cabergoline was reintroduced there was a clinical improvement and
normalization of ACTH plasma levels (64 pg/ml). The MRI analysis of the sella
region demonstrated a complete remission of the pituitary adenoma. The results
obtained show for the first time that a long-term treatment with cabergoline
also brings about a complete remission of Nelson's syndrome in the presence of a
pituitary macroadenoma. The neurotransmitter/neuromodulator dopamine plays an important role in both the
central nervous system and the periphery. In the hypothalamopituitary system its
function is a domit and tonic inhibitory regulation of pituitary hormone
secretion including prolactin- and proopiomelanocortin-derived hormones. It is
well known that dopamine agonists, such as bromocriptine, pergolide,
quinagolide, cabergoline, and lisuride, can inhibit PRL secretion by binding to
the D(2) dopamine receptors located on normal as well as tumorous pituitary
cells. Moreover, they can effectively decrease excessive PRL secretion as well
as the size of the tumor in patients having prolactinoma. Furthermore, dopamine
agonists can also be used in other pituitary tumors. The major requirement for
its use is that the tumor cells should express D(2) receptors. Therefore, in
addition to prolactinomas, targets of dopamine agonist therapy are somatotroph
tumors, nonfunctioning pituitary tumors, corticotroph pituitary tumors, Nelson's
syndrome, gonadotropinomas, and thyrotropin-secreting pituitary tumors. It is
also an option for the treatment of pituitary disease during pregcy.
Differences between the effectiveness and the resistance of different
dopaminergic agents as well as the future perspectives of them in the therapy of
pituitary tumors are discussed. We report the results of long-term (6-year) treatment of Nelson's syndrome with
the long-acting dopamine agonist, cabergoline, in a 55-year-old woman. The
disease presented 26 years after bilateral adrenalectomy and radiation treatment
for Cushing's disease, followed by glucocorticoid and mineralocorticoid
replacement therapy. Signs of Nelson's syndrome included skin and mucosal
hyperpigmentation accompanied by elevated plasma levels of adrenocorticotropic
hormone (ACTH) (984 pmol/l; normal, 2.0-11.5 pmol/l). Magnetic resoce imaging
of the pituitary demonstrated sellar enlargement with a 15 mm macroadenoma. The
patient was initially treated with bromocriptine (10 mg/d) which had no effect
on either ACTH level or tumor mass. Because of visual loss, transsphenoidal
surgery was performed, with partial excision of the adenoma and chiasmal
decompression, followed by radiosurgery. However, ACTH levels improved only
temporarily, and then increased to previous levels. Therefore, cabergoline
treatment (1.5 mg/week) was initiated. ACTH levels decreased dramatically from
1050 to 132 pmol/l, accompanied by clinical improvement. Repeated imaging
studies demonstrated a stable residual pituitary tumor. This case demonstrates
that long-term cabergoline treatment may be efficient in patients with Nelson's
syndrome. PURPOSE: Nelson's syndrome is a severe complication of bilateral adrenalectomy
performed in the treatment of some Cushing's diseases, and its management
remains difficult. Trough the observation of a patient suffering from a severe
form of Nelson's syndrome for more than 10 years, the authors review the
literature and discuss the main current therapeutic possibilities.
CURRENT KNOWLEDGE AND KEY POINTS: Many molecules have been used with variable
results. In our observation cabergoline at 2 mg per week seems to be efficient
after a 3 and a half years follow-up, in accordance with some recent
publications. More than bromocriptine, this dopamine agonist provides
interesting prospects for this disease's management. Moreover, if the
conventional treatments as valproic acid or cyproheptadine are not very
efficient, somatostatin analogs seem to be of some therapeutic interest.
FUTURE PROSPECTS AND PROJECTS: New molecules are currently evaluated, but
studies are difficult to conduct because of the low disease prevalence. Tumour
receptors analysis undoubtedly constitutes an attractive way to find new
therapeutic targets. Introduction. Invasive tumours in Nelson's syndrome need aggressive therapy.
Recent reports have documented the efficacy of temozolomide (TMZ) in the
treatment of adenomas resistant to conventional management. Objective. The
review of the literature concerning TMZ treatment of atypical corticotroph
adenomas and a case study of 56-year-old woman who developed Nelson's syndrome.
Treatment Proceeding. The patient with Cushing's disease underwent
transsphenoidal adenomectomy followed by a 27-month-long period of remission.
Due to a regrowth of the tumor, she underwent two reoperations followed by
stereotactic radiotherapy. Because of treatment failures, bilateral
adrenalectomy was performed. Then she developed Nelson's syndrome. A fourth
transsphenoidal adenomectomy was performed, but there was a rapid recurrence.
Five months later, she underwent a right frontotemporal craniotomy. Due to a
rapid regrowth of the tumour, the patient did not receive gamma-knife therapy
and was treated with cabergoline and somatostatin analogue for some time. Only
TMZ therapy resulted in marked clinical, biochemical, and radiological
improvement. To date, this is the first case of invasive corticotroph adenoma in
Nelson's syndrome treated with temozolomide in Poland. Conclusion. In our
opinion, temozolomide can be an effective treatment option of invasive adenomas
in Nelson's syndrome. |
Are mucins glycosylated proteins? | Yes,
Many members of the mucin family are evolutionarily conserved and are often aberrantly expressed and glycosylated in various benign and malignant pathologies leading to tumor invasion, metastasis, and immune evasion. | Mucin-type O-linked glycosylation, a posttranslational modification affecting
the stability and biophysical characteristics of proteins, requires C1GalT1 (T
synthase) and its obligate, X-linked chaperone Cosmc. Hypomorphic C1GalT1
mutations cause renal failure via not yet established mechanisms. We hypothesize
that impaired Cosmc-dependent O-glycosylation in podocytes is sufficient to
cause disease. Podocyte-specific Cosmc knockout mice were generated and
phenotyped to test this hypothesis. Female heterozygous mice displaying mosaic
inactivation of Cosmc in podocytes due to random X-linked inactivation were also
examined. Mice with podocyte-specific Cosmc deletion develop profound
albuminuria, foot process effacement, glomerular sclerosis, progressive renal
failure, and impaired survival. Glomerular transcriptome analysis reveals early
changes in cell adhesion, extracellular matrix organization, and
chemokine-mediated signaling pathways, coupled with podocyte loss. Expression of
the O-glycoprotein podoplanin was lost, while Tn antigen, representing immature
O-glycans, was most abundantly found on podocalyxin. In contrast to hemizygous
male and homozygous female animals, heterozygous female mosaic animals developed
only mild albuminuria, focal foot process effacement, and nonprogressive kidney
disease. Ultrastructurally, Cosmc-deficient podocytes formed Tn antigen-positive
foot processes interdigitating with those of normal podocytes but not with other
Cosmc-deficient cells. This suggests a cell nonautonomous mechanism for
mucin-type O-glycoproteins in maintaining podocyte function. In summary, our
findings demonstrated an essential and likely cell nonautonomous role for
mucin-type O-glycosylation for podocyte function. Mucin is a glycoprotein that is the primary component of the mucus overlaying
the epithelial tissues. Because mucin functions as a first line of the innate
immune system, Pseudomonas aeruginosa appears to require interaction with mucin
to establish infection in the host. However, the interactions between P.
aeruginosa and mucin have been poorly understood. In this study, using in vivo
expression technology (IVET), we attempted to identify mucin-inducible promoters
that are likely to be involved in the establishment of P. aeruginosa infection.
The IVET analysis revealed that the genes encoding glycosidases, sulfatases, and
peptidases that are thought to be required for the utilization of mucin as a
nutrient are present in 13 genes downstream of the identified promoters. Our
results indicated that, among them, sdsA1 encoding a secreted sulfatase plays a
central role in the degradation of mucin. It was then demonstrated that
disruption of sdsA1 leads to a decreased release of sulfate from mucin and
sulfated sugars. Furthermore, the sdsA1 mutant showed a reduction in the ability
of mucin gel penetration and an attenuation of virulence in leukopenic mice
compared with the wild-type strain. Collectively, these results suggest that
SdsA1 plays an important role as a virulence factor of P. aeruginosa. Many members of the mucin family are evolutionarily conserved and are often
aberrantly expressed and glycosylated in various benign and maligt
pathologies leading to tumor invasion, metastasis, and immune evasion. The large
size and extensive glycosylation present challenges to study the mucin structure
using traditional methods, including crystallography. We offer the hypothesis
that the functional versatility of mucins may be attributed to the presence of
intrinsically disordered regions (IDRs) that provide dynamism and flexibility
and that the IDRs offer potential therapeutic targets. Herein, we examined the
links between the mucin structure and function based on IDRs, posttranslational
modifications (PTMs), and potential impact on their interactome. Using
sequence-based bioinformatics tools, we observed that mucins are predicted to be
moderately (20%-40%) to highly (>40%) disordered and many conserved mucin
domains could be disordered. Phosphorylation sites overlap with IDRs throughout
the mucin sequences. Additionally, the majority of predicted O- and N-
glycosylation sites in the tandem repeat regions occur within IDRs and these
IDRs contain a large number of functional motifs, that is, molecular recognition
features (MoRFs), which directly influence protein-protein interactions (PPIs).
This investigation provides a novel perspective and offers an insight into the
complexity and dynamic nature of mucins. |
Is carpal tunnel syndrome a type of nerve entrapment? | Carpal tunnel syndrome (CTS) is the most frequent entrapment neuropathy in humans. | The carpal tunnel syndrome is the most frequent entrapment syndrome of
peripheral nerves. Either a diminution of the volume of the whole carpal tunnel
or increasement of the intracarpal structures can enhance the pressure on the
median nerve and so develop a carpal tunnel syndrome. Fibrosis or thickening of
the synovia of the wrist joint is the most common cause of the syndrome, that
appears usually in women more than 50 years old. Irradiating pain and sensory
disturbances are the most frequent subjective complaints. Motoric changes appear
in a minority of patients with the syndrome. The operative procedure is done
ambulatory with brachial plexus anesthesia. The subcutaneous 'ramus palmaris
nervi mediani' should be treated carefully when releasing the transverse
ligament. After a mean time of 24.1 months, 28 of carpal tunnel syndromes
treated operatively had a significant amelioration. Seven patients had recurrent
sensible or motoric complaints, one of them was operated on a second time.
Postoperative recurrent carpal tunnel syndrome mostly is due to inadequate
technique or fibrous proliferations. Clinicians commonly observe upper extremity signs and symptoms which result from
median nerve entrapment and can develop at multiple sites along this nerve.
Median nerve entrapment may occur at the distal humerus when the rarely present
ligament of Struthers connects an anomalous bony spur of the humeral shaft to
its medial epicondyle. The pronator syndrome refers to compromise of the median
nerve in the proximal forearm region. This may result from entrapment between
the 2 heads of the pronator teres, between the pronator teres and the flexor
digitorum sublimis, or by the lacertus fibrosus extension from the biceps
tendon. The anterior interosseous branch of the median nerve is subject to
compromise near its origin. As a motor nerve it produces signs of weakness as
indicators of anterior interosseous syndrome. This syndrome usually occurs
spontaneously, but can be caused by fractures and fibrous bands. The carpal
tunnel is a narrow fibro-osseous tunnel through which the median nerve passes
with 9 tendons. Carpal tunnel syndrome is the most common of the median nerve
entrapments. Its causes are many: anything which increases the volume of the
tunnel contents or decreases the size of the tunnel. Electrodiagnostic
abnormalities exist more frequently when this entrapment is present than for
other median nerve entrapments. Anatomic variations of the median nerve occur
frequently and may lead to diagnostic confusion if not recognized. Successful
diagnosis and treatment of median nerve entrapment syndromes require awareness
of possible involved sites and detailed knowledge of related anatomy. Entrapment neuropathies of the upper extremity are common, debilitating
conditions. Most patients with these neuropathies are readily diagnosed on
purely clinical grounds and may be effectively managed with nonoperative
measures. However, the broad differential diagnosis often necessitates
electrodiagnostic testing and radiographic imaging to clarify the situation.
This review focuses on three of the most common entrapment neuropathies in the
upper limbs: carpal tunnel syndrome (median nerve entrapment at the wrist),
cubital tunnel syndrome (ulnar nerve entrapment at the elbow), and radial tunnel
syndrome (posterior interosseous nerve entrapment). Anatomical considerations,
patient evaluation, indications for surgical intervention, options for surgical
approaches, outcomes, and complications are discussed. A case of the entrapment neuropathy of the palmar cutaneous branch of the median
nerve, concomitant with carpal tunnel syndrome is presented. This report
demonstrates that the Semmes-Weinstein monofilament test and nerve conduction
studies can identify entrapment of the palmar cutaneous branch of the median
nerve concomitant with carpal tunnel syndrome. Carpal tunnel syndrome (CTS) is a nerve entrapment disorder, involving the
median nerve when it passes the carpal tunnel at the wrist. Using a case-control
methodology, 312 electrophysiologically confirmed CTS patients with mean age of
51.3+/-9.4 (27-74) years (81.7% women) and 100 controls with mean age of
50.4+/-9.2 (21-88) years (75% women) were examined utilising a questionnaire
similar to the clinical diagnostic criteria of restless legs syndrome (RLS).
Forty-four (14.1%) of the CTS patients have symptoms compatible with restless
hand syndrome compared with none (0%) in the control group (p < 0.0001). The
severity of CTS was not significantly associated with the motor restlessness.
Our observations suggest that entrapment syndromes such as CTS can be associated
with a form of restlessness in the hands, analogous to RLS. Carpal tunnel syndrome is a neuropathy resulting from compression of the median
nerve as it passes through a narrow tunnel in the wrist on its way to the hand.
The lack of precise objective and clinical tests, along with symptoms that are
synonymous with other syndromes in the upper extremity, cause carpal tunnel
syndrome to appear to be a rare entity in athletics. However, it should not be
ruled out as a possible etiology of upper extremity paralysis in the athlete.
More typically, carpal tunnel syndrome is the most common peripheral entrapment
neuropathy encountered in industry. Treatment may include rest and/or splinting
of the involved wrist, ice application, galvanic stimulation, or iontophoresis
to reduce inflammation, and then transition to heat modalities and therapeutic
exercises for developing flexibility, strength, and endurance. In addition, an
ergonomic assessment should be conducted, resulting in modifications to
accommodate the carpal tunnel syndrome patient. Nocturnal pins and needles and other sensory disturbances in the median nerve
innervated fingers are caused by local pressure on this nerve in the carpal
tunnel. Carpal tunnel syndrome is the most frequently encountered peripheral
nerve entrapment. In The Netherlands, the prevalence of carpal tunnel syndrome
is estimated 9% among adult women and 0.6% among adult men. Several risk factors
have been identified. For dental professionals, the most relevant seem forceful
use of the hand during scaling and extractions, use of vibrating ultrasonic
equipment and frequent working with the wrist in flexion or in extension. The
diagnosis of carpal tunnel syndrome is based on the characteristic complaints,
confirmed preferably by abnormal electrophysiological tests. Depending on the
degree of impact on daily functioning, treatment for carpal tunnel syndrome may
be expectative, conservative or surgical. Adjustment of the working conditions
may prevent the development of a carpal tunnel syndrome. BACKGROUND: Carpal tunnel syndrome (CTS) is the most common type of peripheral
nerve entrapment and is a significant cause of morbidity. Carpal tunnel syndrome
(CTS) has more incidences in diabetic patients. It has been suggested that
insulin has an effect on nerve regeneration similar to that of nerve growth
factor (NGF). Therefore, we aimed to evaluate the effectiveness of local insulin
injection on the median nerve in patients with non-insulin-dependent diabetes
mellitus (NIDDM) who have mild-to-moderate carpal tunnel syndrome (CTS).
MATERIALS AND METHODS: We carried out a prospective, randomized, single-blind,
case-controlled study in these patients. We randomly selected 50 patients, 20 of
whom had bilateral mild-moderate CTS. Therefore we had 70 hands and categorized
them into two groups. At the baseline we injected NPH insulin (10U) directly
into the carpal tunnel in group 1, and performed physiotherapy for the other
group (group 2). Two weeks later, NPH insulin (10U) was injected into the carpal
tunnel again and we continued physiotherapy for group 2. Electrodiagnostic study
was performed for these two groups before treatment and 4 weeks after the last
injection and physiotherapy. The patients were followed up for 6 weeks.
RESULTS: In both groups decrement of distal motor latency (DML) of the median
nerves statistically was significant. In both groups, the increment of the
sensory nerve conduction velocity was statistically significant. Also the
decrement of pain, paresthesia, numbness, weakness/clumsiness and nocturnal
awaking was statistically significant in both groups. But there was no
significant difference between the two groups.
CONCLUSION: Local insulin injection is an effective and safe treatment for
carpal tunnel syndrome in NIDDM patients as physiotherapy BACKGROUND: Carpal tunnel syndrome and ulnar nerve entrapment at the elbow are
the most common entrapment neuropathies seen in adults. Surgery for nerve
decompression is a safe and effective treatment option, and is usually performed
under local anesthesia and as an outpatient procedure. This study aimed to
explore patients' satisfaction and other aspects of the overall experience with
this type of surgery.
METHODS: Qualitative research methodology was used. Semi-structured, open-ended
interviews were conducted with 30 adult patients who had undergone carpal tunnel
release or ulnar nerve decompression at the elbow 6-24 months prior. Interviews
were digitally audio recorded and transcribed, and the data subjected to
thematic analysis.
RESULTS: Four overarching themes emerged from the data: (1) most patients did
not perceive their condition to be serious; (2) patients were satisfied with the
overall surgical experience; (3) the outcome was more important to patients than
the process; and (4) majority of patients had a realistic expectation of
outcomes.
CONCLUSIONS: Patients had a positive experience with carpal tunnel and ulnar
nerve decompression surgery, although their level of satisfaction was dependent
on the surgical outcome. Areas requiring improvement, specifically information
about post-operative care and expectations of recovery, will be implemented in
the future care of patients. Guyon's canal syndrome is a compression neuropathy of the ulnar nerve entrapment
at the wrist. Compression of the ulnar nerve at the wrist by a ganglion,
lipomas, diseases of the ulnar artery, fractures of the hamate and trauma are
common etiologcal factors. Unlike Guyon's canal syndrome, carpal tunnel syndrome
(CTS) is the most common nerve entrapment of the upper extremity. Although, open
(OCTR) or endoscopic carpal tunnel release (ECTR) is highly effective in
relieving pain, failure with carpal tunnel release is seldom seen. In this
paper, we presented a patient with ulnar nerve entrapment associated with
recurrent CTS and discussed the possible pathomechanism with a review of current
literature. INTRODUCTION: Carpal tunnel syndrome (CTS) is considered a simple entrapment of
the median nerve at the carpal tunnel. In the last years, several studies have
demonstrated the presence of peripheral and central sensitization mechanisms.
AIM: To review the basis neurophysiology of peripheral and central sensitization
by applying them to CTS and to determine their clinical repercussions.
DEVELOPMENT: Several studies have revealed that patients with CTS exhibit
somato-sensory changes in areas innervated by the median nerve and also in areas
non-related with the median nerve. Individuals with CTS exhibited widespread
mechanical and thermal pain hyperalgesia, although they suffered from unilateral
symptoms. Further, patients also showed wide-spread impairments in vibration
conduction, deficits in fine motor control and changes in the somato-sensory
cortex. These evidences support the presence of a complex process of peripheral
and central sensitization in patients with CTS which may constitute a negative
prognosis factor for the management of these patients.
CONCLUSIONS: The advances in neurosciences in the last years support the
presence of peripheral and central sensitization mechanisms in CTS. These
mechanisms justify the necessity of conceptual changes and in the management,
both conservative and surgical, of this syndrome. Additionally, central
sensitization can also play a relevant role in the prognosis of CTS since it can
constitute a negative prognosis factor for its treatment. BACKGROUND: Carpal tunnel syndrome (CTS) is entrapment of median nerve in carpal
tunnel of the wrist. The prevalence of CTS related to pregcy and
non-pregcy is unknown in some countries such as Iran. The main aim of this
study was to determine the prevalence of CTS in women of Boyerahmad Township
located in South-West part of Iran.
METHODS: This cross-sectional descriptive analytic study was done since February
2010 to January 2011 in Obstetrics and Gynecology clinics in 2656 non-pregt
and 1508 pregt women. The women that had clinical symptoms of CTS performed
standard electro diagnostic techniques for rule in or rule out of CTS.
RESULTS: The prevalence of CTS in pregt and non- pregt women was 3.4 and 2
.3 percent respectively. The prevalence of CTS in all women was 2.7%. Overall,
51 pregt women had CTS that 59.4% had mild, 18.8 % had moderate and 21.9% had
severe CTS. Sixty-one non-pregt women had CTS that 73.6 %had mild, 20.8 %t
had moderate and 5.6 % had severe CTS.
CONCLUSION: Although the prevalence of CTS in Iranian pregcy is higher than
non-pregcy women conservative treatment is safe and more effective. OBJECTIVE: Carpal tunnel syndrome (CTS) is a common median nerve entrapment
neuropathy characterized by pain, paresthesias, diminished peripheral nerve
conduction velocity (NCV) and maladaptive functional brain neuroplasticity. We
evaluated structural reorganization in brain gray (GM) and white (WM) matter and
whether such plasticity is linked to altered median nerve function in CTS.
METHODS: We performed NCV testing, T1-weighted structural MRI, and diffusion
tensor imaging (DTI) in 28 CTS and 28 age-matched healthy controls (HC).
Voxel-based morphometry (VBM) contrasted regional GM volume for CTS versus HC.
Significant clusters were correlated with clinical metrics and served as seeds
to define associated WM tracts using DTI data and probabilistic tractography.
Within these WM tracts, fractional anisotropy (FA), axial (AD) and radial (RD)
diffusivity were evaluated for group differences and correlations with clinical
metrics.
RESULTS: For CTS subjects, GM volume was significantly reduced in contralesional
S1 (hand-area), pulvinar and frontal pole. GM volume in contralesional S1
correlated with median NCV. NCV was also correlated with RD and was negatively
correlated with FA within U-fiber cortico-cortical association tracts identified
from the contralesional S1 VBM seed.
CONCLUSIONS: Our study identified clear morphometric changes in the CTS brain.
This central morphometric change is likely secondary to peripheral nerve
pathology and altered somatosensory afference. Enhanced axonal coherence and
myelination within cortico-cortical tracts connecting primary somatosensory and
motor areas may accompany peripheral nerve deafferentation. As structural
plasticity was correlated with NCV and not symptomatology, the former may be a
better determit of appropriate clinical intervention for CTS, including
surgery. BACKGROUND: Carpal tunnel syndrome (CTS) is by far the most common entrapment
neuropathy (Adams et al. Am J Ind Med 25:527-536, 1994; Cheadle et al. Am J
Public Health 84:190-196, 1994; Stevens et al. Neurology 38:134-138, 1988). A
combination of described symptoms, clinical findings and electrophysiological
testing is used to confirm the diagnosis. Several studies have suggested that in
patients with a clinical diagnosis of CTS, the accuracy of nerve sonography is
similar to that for electromyography (Chen et al. BMC Med Imaging 11:22, 2011;
Guan et al. Neurol Res 33:970-953, 2011; Kele et al. Neurology 61:389-391, 2003;
Tai et al. Ultrasound Med Biol 38:1121-1128, 2012). In special cases though, the
nerve sonography can reveal the cause of the median entrapment neuropathy
(Fumière et al. JBR-BTR 85:1-3, 2002; Kele et al. J Neurosurg 97:471-473, 2002;
Kele et al. Neurology 61:389-391, 2003; Zamora et al. J Clin Ultrasound
39:44-47, 2011).
METHODS: A 43-year-old farmer was admitted to our department with 1 year of
intermittent pain in the left hand and numbness of the thumb, index and middle
finger. The pain and the numbness could be reproduced by extension of the wrist
and fingers. The electrophysiological testing revealed signs of an entrapment
median neuropathy in carpal tunnel.
RESULTS: The high-resolution sonography (18 MHz) revealed signs of entrapment
neuropathy with increased cross-sectional area, disturbed echostructure of the
nerve and pathological wrist-to-forearm ratio, confirming the results from a
similar study (Kele et al. Neurology 61:389-391, 2003). In addition, an
elongated muscle belly of the flexor digitorum superficialis in the carpal
tunnel could be identified. During the extension of the wrist and fingers, a
greater protrusion of the muscle belly could be demonstrated causing compression
of the median nerve.
CONCLUSIONS: We present a video case report of the sonographic findings of a
patient diagnosed with carpal tunnel syndrome due to an elongated muscle belly
of the flexor digitorum superficialis in the carpal tunnel. Our case highlights
the importance of nerve sonography in the differential diagnosis of the cause of
a carpal tunnel syndrome. With the aid of ultrasonography, it is possible to
obtain very important information concerning different aspects of this case.
First, in showing the presence of the elongated muscle belly of the flexor
digitorum superficialis, the cause of the symptoms could be explained. Second,
it was possible through the ultrasound study to explain the atypical clinical
appearance in this case, demonstrating the compression neuropathy only after
extension of the wrist and fingers. There have been no previous reports in which
authors described an elongated muscle belly as cause of a CTS. Third, and
perhaps most important, ultrasonography had a direct influence on our selection
of therapeutical strategy and approach. As a result, we recommended in this
patient a surgical therapy to completely solve the problem, but the patient
declined this option and preferred a conservative therapy with a hand orthosis
to prevent wrist extension. In conclusion we recommend ultrasonography as a very
useful method in the diagnostic evaluation of carpal tunnel syndrome. We have
clearly demonstrated that ultrasonography can be used to discover the cause of
median nerve compression, especially in cases with an atypical clinical
presentation. The carpal tunnel syndrome is the most common entrapment syndrome of the upper
limb. Compression of the median nerve is most often idiopathic and typically
occurs in women aged 50. The diagnosis is clinical and must look for signs of
gravity (hypoesthesia, thenar atrophy). The electromyogram is not required but
recommended for surgical indication, It assesses the severity of the disease and
identifies other injury. Conservative treatment is available in the beginner to
moderate forms. In case of failure of this treatment or with severe objective
signs, treatment is surgical. The ulnar nerve at the elbow comes in the second
position of the upper limb entrapment syndromes. Clinical examination looks for
signs of serious problems with objectives symptoms. Treatment is usually
surgical. Dear sir, one of the most common entrapment neuropathy syndromes in clinical
practice is "Entrapment of median nerve in carpal tunnel" also called "Carpal
tunnel syndrome (CTS)" (Aydin et al., 2007; Huisstede et al., 2010). This
syndrome is caused by entrapment of the median nerve in the wrist (Preston and
Shapiro, 2005) when the pressure increases in the carpal tunnel. A high division
of the median nerve proximal to the carpal tunnel, also known as a bifid median
nerve, is a rare anatomic variation that may be associated with CTS and with
persistent median vessels (Lanz, 1977). This anatomic variation has an incidence
of 0,8% to 2,3% in patients with CTS. Lanz (1977) has characterized this
anatomic condition of the median nerve in the carpal tunnel. These anatomic
variants have been classified into four groups: - Group 0: extraligamentous
thenar branch (standard anatomy); - Group 1: variations of the course of the
thenar branch; - Group 2: accessory branches at the distal portion of the carpal
tunnel; - Group 3: divided or duplicated median nerve inside the carpal tunnel;
- Group 4: accessory branches proximal to the carpal tunnel. During dissection
of the wrist performed for the treatment of a CTS under local anesthesia, we
found an anatomical variation of the median nerve that was divided in two
branches inside the carpal tunnel (Group 3 of Lanz Classification) and in which
its radial branch passed through its own compartment. The two parts of the nerve
seems to be unequal in size (Fig. 1). Moreover the nerve passed in carpal tunnel
associated with a median artery, so we classified this variation in the group 3b
of Lanz Classification (Fig. 2). The persistence of median artery coexisting
with a bifid median nerve has been widely reported in surgical literature (Lanz,
1977; Barbe et al., 2005). Before surgical intervention clinical evaluation of
patient and electrophysiological examination showed no differences compared to a
non bifid median nerve entrapment syndrome. In conclusion the bifid median nerve
may facilitate compression of median nerve in the carpal tunnel because of its
increased cross sectional area even if it has no electrophysiological or
clinical differential diagnosis in case of CTS. The aim of this letter is aware
the physicians in order to borne in mind the possible presence of a median nerve
variation during dissection of carpal tunnel in order to avoid the damage of
this non common anatomical structures. BACKGROUND: Compression of the median nerve at the wrist, or carpal tunnel
syndrome, is the most commonly recognized nerve entrapment syndrome. Carpal
tunnel syndrome is usually caused by compression of the median nerve due to
synovial swelling, tumor, or anomalous anatomical structure within the carpal
tunnel.
METHODS: During a routine carpal tunnel decompression, a large vessel was
identified within the carpal tunnel.
RESULTS: The large vessel was the radial artery. It ran along the radial aspect
of the carpal tunnel just adjacent to the median nerve.
CONCLUSIONS: The unusual presence of the radial artery within the carpal tunnel
could be a contributing factor to the development of carpal tunnel syndrome. In
this case, after surgical carpal tunnel release, all symptoms of carpal tunnel
syndrome resolved. INTRODUCTION: Carpal tunnel syndrome, entrapment of median nerve at the wrist,
is one of the most commonly encountered peripheral neuropathies in the upper
extremity. It is also common in individuals with spinal cord injury due to
repetitive movements during wheelchair use. Although it is well known that
prevalence of carpal tunnel syndrome is high in individuals with spinal cord
injury, no previous study identified aberrant muscle as the cause.
CASE PRESENTATION: A 43-year-old man with T10 incomplete, ASIA Impairment Scale
(AIS) C, patient with paraplegia who is a wheelchair basketball player presented
to our electrodiagnostic laboratory with complaints of bilateral hand numbness
after intensive training for a local veteran wheelchair basketball tournament.
Nerve conduction studies showed carpal tunnel syndrome. Ultrasonographic
assessment of carpal tunnel revealed the presence of abnormal muscle in the
carpal tunnel encroaching the median nerve dynamically.
DISCUSSION: It is important to identify the underlying cause of carpal tunnel
syndrome, which is a common cause of upper extremity impairment in individuals
with spinal cord injury because individuals with spinal cord injury who use
wheelchair depend on their arms for mobility, transfers, and most activities of
daily life. BACKGROUND: Carpal tunnel syndrome (CTS) is the most frequent entrapment
neuropathy in humans. Nonsurgical management is still a matter of debate, and
conservative treatments include splinting, local steroid injections, ultrasound,
and oral steroids. Acupuncture and electroacupuncture therapy for symptomatic
CTS may improve symptoms and aid nerve repair as well as improve sensory and
motor functions. However, limited evidence based on comprehensive evaluation
methods is available regarding the effects of those treatments.
OBJECTIVE: The study intended to compare the short-term effects of acupuncture
and conventional medical treatment on CTS patients' clinical symptoms and on the
results of their electrodiagnostic tests.
DESIGN: The research team designed a randomized controlled trial.
SETTING: The study took place at the electrodiagnostic clinic of the School of
Persian and Complementary Medicine at Mashhad University of Medical Sciences
(Mashhad, Iran).
PARTICIPANTS: Participants were 60 patients at the clinic with the clinical
diagnosis of CTS.
INTERVENTIONS: Participants were randomly assigned to 1 of 2 groups. Patients in
the control group received 100 mg of Celebrex as tablets, 2 times daily.
Patients in the intervention group received 12 sessions of acupuncture, each for
30 min, for 4 wk. The needle insertion points were fixed for all sessions. In
addition, wrist braces were provided to wear at night for 1 mo in both groups.
OUTCOME MEASURES: At baseline, postintervention at the end of week 4, and at a
3-mo follow-up at the end of week 16, participants' clinical symptoms-pain,
numbness, tingling, weakness/clumsiness, and night awakenings-and the results of
their electrodiagnostic studies were evaluated and compared.
RESULTS: In total, 49 patients completed the study-24 in the control group and
25 in the intervention group. Compared with the control group, the intervention
group's clinical symptoms-pain, numbness, tingling, and muscular weakness-based
on the subscales of the global symptoms score questionnaire as well as the
overall score on that questionnaire improved significantly (P < .05). Regarding
the electrodiagnostic studies, only the distal motor latency showed a
significantly greater decrease in the acupuncture group in comparison to
controls (P = .001).
CONCLUSION: All clinical symptoms and the results of the electrodiagnostic tests
improved significantly in the intervention group, and the improvements continued
during the 3 mo postintervention. The therapeutic results of acupuncture were
mostly similar to and in certain cases better than those of the conventional
medical treatment. Therefore, acupuncture can be suggested as a safe and
suitable therapeutic method in CTS. Introduction: Carpal tunnel syndrome (CTS) is an entrapment neuropathy
accounting for up to 90% of nerve compression syndromes. It causes both positive
and negative symptoms in the hands. These symptoms, especially pain, can be
debilitating, which can in turn have a negative effect on patients' quality of
life (QoL). The aim of this cross-sectional case-controlled study was two-fold;
to compare the QoL of patients with CTS and subjects without CTS and to
determine the effect of pain on QoL in patients with CTS.Methods: All patients
underwent nerve conduction studies (NCS) and were classified into mild,
moderate, severe. QoL was assessed via the SF-36 questionnaire.Results:
Fifty-one patients and 45 age- and gender-matched controls were recruited.
Prevalence of pain (determined as scoring 4 or above on a visual analog scale)
in CTS was 39.2%. CTS patient health-related QOL scores were significantly
reduced (p < 0.001) across all of the SF-36 domains, compared to the healthy
control group scores. After adjusting for gender presence of pain was still
significantly negatively correlated with scores for physical functioning (beta
-0.283, p = 0.036).Conclusions: Patients with CTS have a significantly worse QoL
compared to subjects without CTS. In addition, the presence of pain is a
significant determit of physical functioning in patients who have been
diagnosed with CTS. Carpal tunnel syndrome (CTS) is the most common focal entrapment mononeuropathy,
comprising medium nerve chronic inflammation and fibrosis. Although carpal
tunnel release surgery (CTRS) has demonstrated to be effective, around 3% to 25%
of CTRS show recurrence. Amniotic membrane transplantation (AMT) has been used
in different pathologies inhibiting inflammation and fibrosis and promoting
nerve repair. The aim of this study was to determine the efficacy of AMT in
CTRS. The present study comprised a randomized, single-blind controlled trial to
compare the 1-year follow-up outcomes of AMT in CTRS (AMT group) or CTRS alone
(control group) in patients with CTS. Thirty-five patients with unilateral or
bilateral CTS were enrolled, and 47 wrists were randomized into two groups: the
AMT group and the control group. To compare the outcomes, three different
questionnaires scores (Boston Carpal Tunnel Syndrome Questionnaire, Disabilities
of the Arm, Shoulder, and Hand, and Historical-Objective scale) were used.
Evaluations were assessed at baseline and at 15 days, 1, 3, 6, and 12 months
after surgery. Compared with the control group, the AMT group showed significant
(p < 0.05) reductions in all scores from 6 months after surgery until the end of
the study. Both AMT and control groups showed significant intragroup differences
in all scores, since the first month after surgery until the end of the study in
comparison with the baseline scores. Taken together, these results indicate that
CTRS in conjunction with AMT is more effective than CTRS alone in patients with
CTS at 1-year follow-up. Clinical Trial: NCT04075357; Amniotic Membrane in
Carpal Tunnel Syndrome. |
What is the main manifestation of Liebenberg syndrome? | Liebenberg syndrome (MIM 186550) is a very rare autosomal dominant condition characterized by three main features: dysplasia of all of the bony components of the elbow joint, abnormalities in the shape of carpal bones, and brachydactyly. | We report a case of Liebenberg syndrome in a 6-year-old girl, including the
clinical, radiological, angiographic, and operative findings. We note that the
forearm and hand malformations have similarities to leg and foot anatomy. Our
observations may help provide insight into the etiology of this unusual
condition. The Liebenberg syndrome was first described in 1973 in a five- generation
family. A sixth generation was added in 2001, and in 2009 a hitherto unknown
branch of the same family with similar anomalies extended the family tree
significantly. This article describes the clinical findings and illustrates the
abnormalities with radiographs and three-dimensional computed tomography scans.
We discuss the genetic abnormality that causes Liebenberg syndrome, the genomic
rearrangement at the PITX1 locus on chromosome 5.The structural variations seem
to result in an ectopic expression of paired-like homeodomain transcription
factor 1 (PITX1) in the forelimb causing a partial arm-to-leg transformation in
these patients. |
Which IDH inhibitors by Agios Pharmaceuticals have been approved by the FDA? | Enasidenib and ivosidenib, the IDH2 and IDH1 inhibitors developed by Agios Pharmaceuticals, have been approved by the Food and Drug Administration | Isocitrate dehydrogenase (IDH) is a key enzyme involved in the conversion of
isocitrate to α-ketoglutarate (α-KG) in the tricarboxylic acid (TCA) cycle. IDH
mutation produces a neomorphic enzyme, which can lead to the abnormal
accumulation of R-2-HG and promotes leukemogenesis. IDH mutation occurs in 20%
of acute myeloid leukemia (AML) patients, mainly including IDH1 R132, IDH2 R140,
and IDH2 R172. Different mutant isoforms have different prognostic values. In
recent years, IDH inhibitors have shown good clinical response in AML patients.
Hence, enasidenib and ivosidenib, the IDH2 and IDH1 inhibitors developed by
Agios Pharmaceuticals, have been approved by the Food and Drug Administration on
1 August 2017 and 20 July 2018 for the treatment of adult relapsed or refractory
(R/R) AML with IDH2 and IDH1 mutations, respectively. IDH inhibitor monotherapy
for R/R AML is efficacious and safe; however, there are problems, such as
primary or acquired resistance. Clinical trials of IDH inhibitors combined with
hypomethylating agents or standard chemotherapy for the treatment of R/R AML or
newly diagnosed AML, as well as in post hematopoietic stem cell transplantation
as maintece therapy, are ongoing. This article summarizes the use of IDH
inhibitors in AML with IDH mutations. |
What is RADICL-seq? | Mammalian genomes encode tens of thousands of noncoding RNAs. Most noncoding transcripts exhibit nuclear localization and several have been shown to play a role in the regulation of gene expression and chromatin remodeling. To investigate the function of such RNAs, methods to massively map the genomic interacting sites of multiple transcripts have been developed; however, these methods have some limitations. RNA And DNA Interacting Complexes Ligated and sequenced (RADICL-seq) is a technology that maps genome-wide RNA-chromatin interactions in intact nuclei. RADICL-seq is a proximity ligation-based methodology that reduces the bias for nascent transcription, while increasing genomic coverage and unique mapping rate efficiency compared with existing methods. RADICL-seq identifies distinct patterns of genome occupancy for different classes of transcripts as well as cell type-specific RNA-chromatin interactions, and highlights the role of transcription in the establishment of chromatin structure. | |
Which disease is treated with Anti–Siglec-8 Antibody? | Anti-Siglec-8 Antibody was shown to be effective for Eosinophilic Gastritis and Duodenitis. It is also undergoing clinical investigation for treatment of allergic, inflammatory, and proliferative diseases. | PURPOSE OF REVIEW: Hypereosinophilic syndrome (HES) is characterized by
persistent hypereosinophilia associated with end-organ damage. As our
understanding of the pathogenesis of various forms of HES broadens, so does our
ability to tailor steroid-sparing therapies for each subtype. The purpose of
this review is to summarize recent literature related to the etiology,
diagnosis, and management of HES.
RECENT FINDINGS: Mutations involved in subsets of HES can guide the choice of
tyrosine kinase inhibitors beyond just imatinib. Several biologics that target
interleukin-5 or its receptor have shown beneficial and selective
eosinophil-reducing effects in clinical trials for asthma and other disorders
including HES. Early clinical data with emerging therapies such as
dexpramipexole and anti-Siglec-8 antibody show promise, but need to be confirmed
in randomized trials. Several new biologics and tyrosine kinase inhibitors have
been shown to lower eosinophil numbers, but more randomized trials are needed to
confirm efficacy in HES. INTRODUCTION: Pathologic accumulation and activation of mast cells and
eosinophils are implicated in allergic and inflammatory diseases. Sialic
acid-binding immunoglobulin-like lectin (Siglec)-8 is an inhibitory receptor
selectively expressed on mast cells, eosinophils and, at a lower extent,
basophils. When engaged with an antibody, Siglec-8 can induce apoptosis of
activated eosinophils and inhibit mast cell activation. AK002 is a humanized,
non-fucosylated IgG1 anti-Siglec-8 antibody undergoing clinical investigation
for treatment of allergic, inflammatory, and proliferative diseases. Here we
examine the human tissue selectivity of AK002 and evaluate the in vitro, ex
vivo, and in vivo activity of AK002 on eosinophils and mast cells.
METHODS: The affinity of AK002 for Siglec-8 and CD16 was determined by biolayer
interferometry. Ex vivo activity of AK002 on human eosinophils from blood and
dissociated human tissue was tested in apoptosis and antibody-dependent
cell-mediated cytotoxicity (ADCC) assays. The in vivo activity of a murine
precursor of AK002 (mAK002) was tested in a passive systemic anaphylaxis (PSA)
humanized mouse model.
RESULTS: AK002 bound selectively to mast cells, eosinophils and, at a lower
level, to basophils in human blood and tissue and not to other cell types
examined. AK002 induced apoptosis of interleukin-5-activated blood eosinophils
and demonstrated potent ADCC activity against blood eosinophils in the presence
of natural killer cells. AK002 also significantly reduced eosinophils in
dissociated human lung tissue. Furthermore, mAK002 prevented PSA in humanized
mice through mast cell inhibition.
CONCLUSION: AK002 selectively evokes potent apoptotic and ADCC activity against
eosinophils and prevents systemic anaphylaxis through mast cell inhibition. Aberrant accumulation and activation of eosinophils and potentially mast cells
(MCs) contribute to the pathogenesis of eosinophilic gastrointestinal diseases
(EGIDs), including eosinophilic esophagitis (EoE), gastritis (EG), and
gastroenteritis (EGE). Current treatment options, such as diet restriction and
corticosteroids, have limited efficacy and are often inappropriate for chronic
use. One promising new approach is to deplete eosinophils and inhibit MCs with a
monoclonal antibody (mAb) against sialic acid-binding immunoglobulin-like lectin
8 (Siglec-8), an inhibitory receptor selectively expressed on MCs and
eosinophils. Here, we characterize MCs and eosinophils from human EG and EoE
biopsies using flow cytometry and evaluate the effects of an anti-Siglec-8 mAb
using a potentially novel Siglec-8-transgenic mouse model in which EG/EGE was
induced by ovalbumin sensitization and intragastric challenge. MCs and
eosinophils were significantly increased and activated in human EG and EoE
biopsies compared with healthy controls. Similar observations were made in
EG/EGE mice. In Siglec-8-transgenic mice, anti-Siglec-8 mAb administration
significantly reduced eosinophils and MCs in the stomach, small intestine, and
mesenteric lymph nodes and decreased levels of inflammatory mediators. In
summary, these findings suggest a role for both MCs and eosinophils in EGID
pathogenesis and support the evaluation of anti-Siglec-8 as a therapeutic
approach that targets both eosinophils and MCs. BACKGROUND: Eosinophilic gastritis and duodenitis are characterized by
gastrointestinal mucosal eosinophilia, chronic symptoms, impaired quality of
life, and a lack of adequate treatments. Mast-cell activity may contribute to
the pathogenesis of the conditions. AK002 (lirentelimab) is an anti-Siglec-8
antibody that depletes eosinophils and inhibits mast cells and that has shown
potential in animal models as a treatment for eosinophilic gastritis and
duodenitis.
METHODS: In this phase 2 trial, we randomly assigned adults who had symptomatic
eosinophilic gastritis, eosinophilic duodenitis, or both conditions in a 1:1:1
ratio to receive four monthly infusions of low-dose AK002, high-dose AK002, or
placebo. The primary end point was the change in gastrointestinal eosinophil
count from baseline to 2 weeks after the final dose; to maximize statistical
power, we evaluated this end point in the placebo group as compared with the
combined AK002 group. Secondary end points were treatment response (>30%
reduction in total symptom score and >75% reduction in gastrointestinal
eosinophil count) and the change in total symptom score.
RESULTS: Of the 65 patients who underwent randomization, 43 were assigned to
receive AK002 and 22 were assigned to receive placebo. The mean percentage
change in gastrointestinal eosinophil count was -86% in the combined AK002
group, as compared with 9% in the placebo group (least-squares mean difference,
-98 percentage points; 95% confidence interval [CI], -121 to -76; P<0.001).
Treatment response occurred in 63% of the patients who received AK002 and in 5%
of the patients who received placebo (difference, 58 percentage points; 95% CI,
36 to 74; P<0.001). The mean change in total symptom score was -48% with AK002
and -22% with placebo (least-squares mean difference, -26 percentage points; 95%
CI, -44 to -9; P = 0.004). Adverse events associated with AK002 were similar to
those with placebo, with the exception of higher percentages of patients having
mild-to-moderate infusion-related reactions with AK002 (60% in the combined
AK002 group and 23% in the placebo group).
CONCLUSIONS: In patients with eosinophilic gastritis or duodenitis, AK002
reduced gastrointestinal eosinophils and symptoms. Infusion-related reactions
were more common with AK002 than with placebo. (Funded by Allakos; ENIGMA
ClinicalTrials.gov number, NCT03496571.). |
What is known about mammalian melatonin receptors? | Melatonin receptors MT1 and MT2 (genes officially named MTNR1A and MTNR1B, respectively) play crucial roles in melatonin-mediated regulation of circadian rhythms, the immune system, and control of reproduction in seasonally breeding animals.
The melatonin receptor family is a small group of receptors within the G protein-coupled receptor (GPCR) superfamily. The group comprises of three subtypes which bind melatonin and one member, the melatonin related receptor (MRR), that shares >40% sequence identity with the other melatonin receptors but does not bind melatonin. | The pineal hormone, melatonin, is an important regulator of seasonal
reproduction and circadian rhythms. Its effects are mediated via high-affinity
melatonin receptors, located on cells of the pituitary pars tuberalis (PT) and
suprachiasmatic nucleus (SCN), respectively. Two subtypes of mammalian melatonin
receptors have been cloned and characterized, the MT1 (Mel(1a)) and the MT2
(Mel(1b)) melatonin receptor subtypes. Both subtypes are members of the
seven-transmembrane G protein-coupled receptor family. By using recombit
melatonin receptors it has been shown that the MT1 melatonin receptor is coupled
to different G proteins that mediate adenylyl cyclase inhibition and
phospholipase C beta activation. The MT2 receptor is also coupled to inhibition
of adenylyl cyclase and additionally it inhibits the soluble guanylyl cyclase
pathway. In mice with a targeted deletion of the MT1 receptor, the acute
inhibitory effects of melatonin on SCN multiunit activity are completely
abolished, while the phase-shifting responses to melatonin (given in
physiological concentrations) appear normal. Furthermore, melatonin inhibits the
phosphorylation of the transcription factor cyclic AMP response element binding
protein, induced by the pituitary adenylate cyclase-activating polypeptide in
SCN cells predomitly via the MT1 receptor. However, a functional MT2 receptor
in the rodent SCN is partially able to compensate for the absence of the MT1
receptor in MT1 receptor-deficient mice. These findings indicate redundant and
non-redundant roles of the receptor subtypes in regulating SCN function. In the
PT, a functional MT1 receptor is essential for the rhythmic synthesis of the
clock gene product mPER1. Melatonin produces a long-lasting sensitization of
adenylyl cyclase and thus amplifies cyclic AMP signaling when melatonin levels
decline at dawn. This action of melatonin amplifies gene expression rhythms in
the PT and provides a mechanism for reinforcing rhythmicity in peripheral
tissues which themselves lack the capacity for self-sustained oscillation. Mice
with targeted deletion of melatonin receptor subtypes provide an excellent model
to understand cellular mechanisms through which melatonin modulates circadian
and photoperiodic rhythmicity. |
What is holoprosencephaly? | Holoprosencephaly (HPE) is a congenital defect of the brain, median structures, and face resulting from an incomplete cleavage of the primitive brain during early embryogenesis . The most common developmental defect is characterized by inadequate or absent midline division of the forebrain into cerebral hemispheres with concomitant midline facial defects in the majority of cases . | Holoprosencephaly is a brain anomaly of varying severity with associated
extracranial, symptomatic abnormalities in only a minority of cases. The class
of brain defects known as holoprosencephaly represents a continuum usually
divided into three types: alobar, semilobar, and lobar. Each has both
distinctive radiological characteristics and some similarities. Typical facial
anomalies are found in the severe forms. Absent septum pellucidum and
septo-optic dysplasia, possibly of similar embryological origin, have some
resemblances to lobar holoprosencephaly, but are clinically and radiologically
separate in most instances. Agenesis of the corpus callosum, which is
superficially like holoprosencephaly, should not be confused with the
prosencephalic defects. Holoprosencephaly is a brain defect resulting from incomplete cleavage of the
embryonic forebrain. It involves forebrain and facial malformations that can
range from mild to severe. The epidemiology of holoprosencephaly is largely
unknown. Published prevalence estimates have been derived from clinic-based case
series, and suggested risk factors for holoprosencephaly have been identified in
case reports, without confirmation from systematically conducted
population-based studies. Using data from a population-based birth defects
registry in California, we describe the epidemiologic and clinical
characteristics of cytogenetically and phenotypically distinct types of
holoprosencephaly. A total of 121 cases was identified among a cohort of
1,035,386 live births and fetal deaths. The prevalence of holoprosencephaly was
1.2 per 10,000 births (95% confidence interval 1.0-1.4 per 10,000). Of all
cases, 41% (50/121) had a chromosomal abnormality, most commonly Trisomy 13.
Among the 71 cytogenetically apparently normal cases, 18 had recognizable
syndromes and the remaining 53 were of unknown cause. Among the cytogenetically
abnormal cases, females had a greater risk than males (odds ratio = 2.3,95%
confidence interval [1.2, 4.4]). Among the cytogenetically normal cases,
increased risks were observed among Hispanic whites (OR = 1.8 [0.9, 3.6]) and
cases whose mother was born in Mexico (OR = 2.2 [1.0, 4.5]). Approximately 46%
of all cases had alobar holoprosencephaly, the most severe form of the forebrain
malformation. The facial phenotype did not strongly predict the severity of the
brain defect; however, severity was inversely correlated with length of
survival. This study is the first to present findings based on such a large
population-based series of infants/fetuses affected by holoprosencephaly, and
demonstrates the importance of investigating the component subgroups of this
rare phenotype. PURPOSE OF REVIEW: Holoprosencephaly is a disorder of forebrain development
characterized by a failure of the brain to separate into two hemispheres during
early development. It is now clear that many cases of holoprosencephaly are
caused by alterations in the genetic programmes that pattern the nervous system.
Less is known about how a holoprosencephalic brain either forms or fails to form
connections between various brain structures.
RECENT FINDINGS: Abnormalities in the corpus callosum, corticospinal tract,
medial lemniscus and cerebellar peduncles can be seen in holoprosencephaly.
Diffusion tensor imaging has been and will continue to be an important tool for
imaging white matter in the brain, and will be reviewed here. Furthermore,
recent evidence suggests that holoprosencephaly can be associated with delays or
abnormalities in myelination. The functional implications of white matter
abnormalities in children with holoprosencephaly is only beginning to be
understood.
SUMMARY: Modern neuroimaging has led to a better appreciation of the variability
seen in holoprosencephaly, an anomaly known to have multiple etiologies. Recent
reviews of the biology of holoprosencephaly identify the condition as a defect
in dorsoventral patterning. More detailed white and grey matter
structure-function studies are likely to shed light on how a brain with
drastically altered composition and connectivity does or does not organize
itself to accomplish increasingly complex developmental functions. Holoprosencephaly is a rare brain abnormality resulting from an incomplete
cleavage of the primitive prosencephalon of forebrain during early
embryogenesis. It includes a series of rare complex and heterogenosis disorders.
Alobar form is associated with an extremely poor fetal prognosis. Here we report
three cases of alobar holoprosencephaly and one case of semilobar
holoprosencephaly diagnosed at the third trimester. Causes, diagnosis and
management of holoprosencephaly are discussed referring to literature. Holoprosencephaly is the most common malformation of the forebrain and typically
results in severe neurocognitive impairment with accompanying midline facial
anomalies. Holoprosencephaly is heterogeneous and may be caused by chromosome
aberrations or environmental factors, occur in the context of a syndrome or be
due to heterozygous mutations in over 10 identified genes. The presence of these
mutations may result in an extremely wide spectrum of severity, ranging from
brain malformations incompatible with life to individuals with normal brain
findings and subtle midline facial differences. Typically, clinicians regard
intellectual disability as a sign that a parent or relative of a severely
affected patient may be a mildly affected mutation 'carrier' with what is termed
microform holoprosencephaly. Here we present 5 patients with clear phenotypic
signs of microform holoprosencephaly, all of whom have evidence of above-average
intellectual function. In 4 of these 5 individuals, the molecular cause of
holoprosencephaly has been identified and includes mutations affecting SHH,
SIX3, GLI2, and FGF8. This report expands the phenotypic spectrum of
holoprosencephaly and is important in the counseling of patient and affected
families. Holoprosencephaly is a clinically and genetically heterogeneous midline brain
malformation associated with neurologic manifestations including developmental
delay, intellectual disability and seizures. Although mutations in the sonic
hedgehog gene SHH and more than 10 other genes are known to cause
holoprosencephaly, many patients remain without a molecular diagnosis. Here we
show that a homozygous truncating mutation of STIL not only causes severe
autosomal recessive microcephaly, but also lobar holoprosencephaly in an
extended consanguineous Pakistani family. STIL mutations have previously been
linked to centrosomal defects in primary microcephaly at the MCPH7 locus. Our
results thus expand the clinical phenotypes associated with biallellic STIL
mutations to include holoprosencephaly. Holoprosencephaly (HPE) is the most common developmental defect of the forebrain
characterized by inadequate or absent midline division of the forebrain into
cerebral hemispheres, with concomitant midline facial defects in the majority of
cases. Understanding the pathogenesis of HPE requires knowledge of the
relationship between the developing brain and the facial structures during
embryogenesis. A number of signaling pathways control and coordinate the
development of the brain and face, including Sonic hedgehog, Bone morphogenetic
protein, Fibroblast growth factor, and Nodal signaling. Mutations in these
pathways have been identified in animal models of HPE and human patients.
Because of incomplete penetrance and variable expressivity of HPE, patients
carrying defined mutations may not manifest the disease at all, or have a
spectrum of defects. It is currently unknown what drives manifestation of HPE in
genetically at-risk individuals, but it has been speculated that other gene
mutations and environmental factors may combine as cumulative insults. HPE can
be diagnosed in utero by a high-resolution prenatal ultrasound or a fetal
magnetic resoce imaging, sometimes in combination with molecular testing from
chorionic villi or amniotic fluid sampling. Currently, there are no effective
preventive methods for HPE. Better understanding of the mechanisms of
gene-environment interactions in HPE would provide avenues for such
interventions. Structural malformations of the brain are an important cause of childhood
mortality and morbidity, with the latter having long-term ficial and
psychosocial implications for the affected child and family. Holoprosencephaly
(HPE) is a severe brain malformation characterized by abnormal cleavage of the
prosencephalon in the 5th gestational week. Aprosencephaly and atelencephaly
occur earlier because of failure in the formation of the prosencephalon and
telencephalon, respectively. The HPE holoprosencephaly spectrum classically
includes alobar, semilobar, and lobar forms, although there are no clear-cut
defining features. The middle interhemispheric variant (MIH), also known as
syntelencephaly, is classified as a variant of HPE holoprosencephaly with
midline interhemispheric fusion. Other conditions sometimes included in the
spectrum of HPE holoprosencephaly include septo-optic dysplasia (SOD); "minimal"
HPE holoprosencephaly , which is associated with subtle craniofacial
malformations and mild developmental delay; and microform HPE holoprosencephaly
, which by definition excludes brain involvement. The focus of this article will
be on the spectrum of findings visible in fetal manifestation of the HPE
holoprosencephaly spectrum. Brain embryology; the imaging characteristics,
epidemiology, and embryology of HPE; and the more common associated anomalies,
particularly those of the face ("the face predicts the brain") are reviewed.
Recognition of these anomalies is important for accurate parental counseling,
since the prognosis is poor but not invariably lethal; children with the milder
forms may live well into their teens with severe developmental delays, endocrine
dysfunction, and disrupted homeostasis. Available data on outcome in surviving
children are summarized. Illustrative fetal ultrasonographic and magnetic
resoce images are presented with clinical, autopsy, and postnatal imaging
correlation. BACKGROUND: Holoprosencephaly is a structural anomaly of the brain that consists
in a defect of the prosencephalon development that leads to face and
neurological defects of variable intensity.
AIM: To estimate holoprosencephaly prevalence at birth.
PATIENTS AND METHODS: All cases of holoprosencephaly, born alive or stillbirths,
registered in the 15 Chilean Hospitals of the Latin American Collaborative Study
of Congenital Malformations (ECLAMC) between 1972 and 2012, were studied.
Craniofacial and other anomalies found in newborns affected by holoprosencephaly
are described.
RESULTS: Fifty five cases of holoprosencephaly (58% males) were found among the
798.222 registered births (rendering a prevalence at birth of 0.69 per 10.000
newborns). The most common cranial defect was medial cleft lip with cleft palate
(27.3%), bilateral cleft lip (11%) or both (38.2%), cyclopia (14%), single
nostril (10.9%) and proboscis (9.1%). Eleven percent cases had a trisomy 13. A
slight increase in prevalence over time was observed.
CONCLUSIONS: Holoprosencephaly has a low frequency in Chile and is associated to
trisomy 13. The increase in prevalence could be explained by a better prenatal
diagnosis (ultrasonography). BACKGROUND AND PURPOSE: Holoprosencephaly is a rare developmental brain
abnormality with a range of severity. We describe our experience in diagnosing
holoprosencephaly in the fetus with in utero MR imaging. We hypothesized that
including in utero MR imaging in the diagnostic pathway will improve the
detection of holoprosencephaly compared with ultrasonography and allow better
assessment of the severity.
MATERIALS AND METHODS: We report on holoprosencephaly identified from
ultrasonography and/or a diagnosis of holoprosencephaly made with in utero MR
imaging. We compare the diagnoses made with sonography and in utero MR imaging
in each case and compare the 2 methods of assessing the severity of
holoprosencephaly.
RESULTS: Thirty-five fetuses are reported, including 9 in which the diagnosis of
holoprosencephaly was made on ultrasonography but not confirmed on in utero MR
imaging. Of the 26 cases of holoprosencephaly diagnosed on in utero MR imaging,
12 were not recognized on ultrasonography.
CONCLUSIONS: Our results show that in utero MR imaging has a major role in
diagnosing or refuting a diagnosis of fetal holoprosencephaly made on
ultrasonography. In utero MR imaging also assists in grading the severity of
fetal holoprosencephaly. Holoprosencephaly is a brain malformation that develops as a result of a defect
in development of prosencephalon during early gestation. Holoprosencephaly can
be diagnosed with prenatal ultrasonography and magnetic resoce imaging. We
report herein a case with cyclopia and holoprosencephaly detected by prenatal
ultrasonography. Holoprosencephaly is a spectrum of congenital defects of forebrain development
characterized by incomplete separation of the cerebral hemispheres. In vivo
diagnosis can be established with prenatal brain imaging and disease severity
correlates with extent of abnormally developed brain tissue. Advances in
magnetic resoce imaging (MRI) over the past 25 years and their application to
the fetus have enabled diagnosis of holoprosencephaly in utero. Here, we report
on the prenatal diagnosis of holoprosencephaly using MRI as part of a diagnostic
and management evaluation at a tertiary and quaternary referral center. Using an
advanced MRI protocol and a 1.5-Tesla magnet, we show radiographic data
diagnostic for the holoprosencephaly spectrum, including alobar, semilobar,
lobar, middle interhemispheric, and septopreoptic variant. Accurate prenatal
evaluation is important because the severity of imaging findings correlates with
postnatal morbidity and mortality in holoprosencephaly. Therefore, this work has
implications for the evaluation, diagnosis, management, and genetic counseling
that families can receive during a pregcy. Holoprosencephaly (HPE) is a congenital defect of the brain, median structures,
and face resulting from an incomplete cleavage of the primitive brain during
early embryogenesis. The authors report a case of trisomy 13 syndrome diagnosed
at prenatal follow up. The preterm newborn lived only 5 hours, and died because
of severe respiratory failure. The autopsy findings disclosed facial, skull,
limbs, cardiac, and cerebral malformations. Among the latter, the presence of
alobar HPE, the central theme of this report, was evident. The most common
nonrandom chromosomal abnormality in patients with HPE is trisomy 13. The most
severe variant, namely alobar HPE, is shown in this case report. Discussion on
this severe anomaly, along with the case report with details of Patau's
syndrome, is the goal of this report. BACKGROUND: Holoprosencephaly is the most common malformation of the forebrain
(1 in 250 embryos) with severe consequences for fetal and child development.
This study evaluates nongenetic factors associated with holoprosencephaly risk,
severity, and gene-environment interactions.
METHODS: For this retrospective case control study, we developed an online
questionnaire focusing on exposures to common and rare toxins/toxicants before
and during pregcy, nutritional factors, maternal health history, and
demographic factors. Patients with holoprosencephaly were primarily ascertained
from our ongoing genetic and clinical studies of holoprosencephaly. Controls
included children with Williams-Beuren syndrome (WBS) ascertained through online
advertisements in a WBD support group and fliers.
RESULTS: Difference in odds of exposures between cases and controls as well as
within cases with varying holoprosencephaly severity were studied. Cases
included children born with holoprosencephaly (n = 92) and the control group
consisted of children with WBS (n = 56). Pregcy associated risk associated
with holoprosencephaly included maternal pregestational diabetes (9.2% of cases
and 0 controls, p = .02), higher alcohol consumption (adjusted odds ratio [aOR],
1.73; 95% CI, 0.88-15.71), and exposure to consumer products such as aerosols or
sprays including hair sprays (aOR, 2.46; 95% CI, 0.89-7.19). Significant
gene-environment interactions were identified including for consumption of
cheese (p < .05) and espresso drinks (p = .03).
CONCLUSION: The study identifies modifiable risk factors and gene-environment
interactions that should be considered in future prevention of
holoprosencephaly. Studies with larger HPE cohorts will be needed to confirm
these findings. |
What is the effect of notch in the division of neural progenitor cells in Drosophila? | The Notch pathway mediates the differentiation of neural progenitor cells in Drosophila. It's an important part of the development of neural stem cells, which are the cells that make up the brain. Notch/HES signaling and MIR-9 signaling are very important for the homeostasis of neural cells. It is thought that notch activation is responsible for the growth of neurons. | Asymmetric division is a fundamental mechanism for generating cellular
diversity. Studies on Drosophila neural progenitors have provided valuable
insight into how evolutionarily conserved protein cassettes may be
differentially deployed in different developmental contexts to mediate
asymmetric divisions. Recent findings also suggest possible mechanisms by which
the processes of cell-cycle progression, neuronal lineage development and
asymmetric divisions may be integrated. Notch signaling is involved in a variety of cell-fate decisions during
development. Here we investigate the role of Notch signaling in apoptotic cell
death of neural progenitors through the generation and analysis of cell
type-specific conditional transgenic and knockout mice. We show that conditional
expression of a constitutively active form of Notch1 in early neural progenitor
cells, but not postmitotic neurons, selectively induces extensive apoptosis,
resulting in a markedly reduced progenitor population. Conversely, attenuation
of Notch signaling in Notch1 conditional knockout or Presenilin-1-/- mice
results in reduced apoptosis of early neural progenitor cells. Furthermore,
Notch activation in neural progenitor cells leads to elevated levels of nuclear
p53 and transcriptional upregulation of the target genes Bax and Noxa, and the
promotion of apoptotic cell death by Notch activation is completely suppressed
by p53 deficiency. Together, these complementary gain-of-function and
loss-of-function studies reveal a previously unappreciated role of Notch
signaling in the regulation of apoptotic cell death during early mammalian
neural development. A complete account of the whole developmental process of neurogenesis involves
understanding a number of complex underlying molecular processes. Among them,
those that govern the crucial transition from proliferative (self-replicating)
to neurogenic neural progenitor (NP) cells remain largely unknown. Due to its
sequential rostro-caudal gradients of proliferation and neurogenesis, the
prospective spinal cord of the chick embryo is a good experimental system to
study this issue. We report that the NOTCH ligand DELTA-1 is expressed in
scattered cycling NP cells in the prospective chick spinal cord preceding the
onset of neurogenesis. These Delta-1-expressing progenitors are placed in
between the proliferating caudal neural plate (stem zone) and the rostral
neurogenic zone (NZ) where neurons are born. Thus, these Delta-1-expressing
progenitors define a proliferation to neurogenesis transition zone (PNTZ). Gain
and loss of function experiments carried by electroporation demonstrate that the
expression of Delta-1 in individual progenitors of the PNTZ is necessary and
sufficient to induce neuronal generation. The activation of NOTCH signalling by
DELTA-1 in the adjacent progenitors inhibits neurogenesis and is required to
maintain proliferation. However, rather than inducing cell cycle exit and
neuronal differentiation by a typical lateral inhibition mechanism as in the NZ,
DELTA-1/NOTCH signalling functions in a distinct manner in the PNTZ. Thus, the
inhibition of NOTCH signalling arrests proliferation but it is not sufficient to
elicit neuronal differentiation. Moreover, after the expression of Delta-1 PNTZ
NP continue cycling and induce the expression of Tis21, a gene that is
upregulated in neurogenic progenitors, before generating neurons. Together,
these experiments unravel a novel function of DELTA-NOTCH signalling that
regulates the transition from proliferation to neurogenesis in NP cells. We
hypothesize that this novel function is evolutionary conserved. In the developing mammalian nervous system, neural progenitor cells first
express the Notch effector Hes1 at variable levels and then proneural genes and
Notch ligands in salt-and-pepper patterns. Recent real-time imaging analysis
indicates that Hes1 expression in these cells oscillates with a period of about
2-3 h. Furthermore, the proneural gene Neurogenin-2 (Ngn2) and the Notch ligand
gene Deltalike-1 (Dll1) are expressed cyclically in neural progenitor cells
under the control of Hes1 oscillation but are expressed continuously in
postmitotic neurons, which lose Hes1 expression. Hes1-driven Ngn2 and Dll1
oscillations seem to be advantageous for maintece of a group of cells in an
undifferentiated state by mutual activation of Notch signaling. This dynamic
mode of gene expression would require a revision of the traditional view of how
Notch-mediated lateral inhibition operates in the developing mammalian nervous
system. Molecular mechanisms by which stroke increases neurogenesis have not been fully
investigated. Using neural progenitor cells isolated from the subventricular
zone (SVZ) of the adult rat subjected to focal cerebral ischemia, we
investigated the Notch pathway in regulating proliferation and differentiation
of adult neural progenitor cells after stroke. During proliferation of neural
progenitor cells, ischemic neural progenitor cells exhibited substantially
increased levels of Notch, Notch intracellular domain (NICD), and hairy enhancer
of split (Hes) 1, which was associated with a significant increase of
proliferating cells. Blockage of the Notch pathway by short interfering
ribonucleic acid (siRNA) against Notch or a gamma secretase inhibitor
significantly reduced Notch, NICD and Hes1 expression and cell proliferation
induced by stroke. During differentiation of neural progenitor cells, Notch and
Hes1 expression was downregulated in ischemic neural progenitor cells, which was
coincident with a significant increase of neuronal population. Inhibition of the
Notch pathway with a gamma secretase inhibitor further substantially increased
neurons, but did not alter astrocyte population in ischemic neural progenitor
cells. These data suggest that the Notch signaling pathway mediates adult SVZ
neural progenitor cell proliferation and differentiation after stroke. In the adult mammalian brain niches for neural stem cells are maintained, which
enable a steady-state neurogenesis. This process is tightly regulated by
multiple niche factors, including Notch and NF-κB signaling. The
NF-κB-activating-protein (NKAP) has previously been shown to act as Notch
co-repressor component by binding CIR and recruiting HDAC3 in T-cell development
and furthermore to regulate NF-κB-dependent transcription. Here, we provide
first evidence for the expression of NKAP in neurogenic cells of the adult
mammalian brain. NKAP is highly expressed in Mash1(+) transit amplifying cells
and PSA-NCAM(+) migrating neuroblasts throughout the subventricular zone (SVZ)
and the rostral migratory stream (RMS), as well as in the hippocampus. We
further show that NKAP expression levels are downregulated during the course of
the RMS. Eventually, most differentiated cells in the olfactory bulb (OB) and
the corpus callosum only display low levels of NKAP expression. Finally, large
subsets of mature neurons in the OB, the hippocampus and the thalamus express
NKAP at high levels, suggesting an additional role of NKAP outside of SVZ
progenitor cells. Asymmetric division of neural progenitor cells is a crucial event in the
generation of neuronal diversity and involves the segregation of distinct
proteins into daughter cells, thereby promoting unique differentiation programs.
Although it was known that Notch signaling acts postmitotically to orchestrate
differentiation of daughter cells from asymmetrically dividing precursor cells,
Bhat reported a previously uncharacterized role for Notch that occurs before
cell division to promote the asymmetric localization of the protein Numb and the
positioning of the cleavage furrow. Numb is an inhibitor of Notch activity;
thus, this mechanism forms a regulatory feedback loop to control asymmetric
cytokinesis and differentiation. The Notch signaling pathway plays essential roles in both animal development and
human disease. Regulation of Notch receptor levels in membrane compartments has
been shown to affect signaling in a variety of contexts. Here we used
steady-state and pulse-labeling techniques to follow Notch receptors in sensory
organ precursor cells in Drosophila. We find that the endosomal adaptor protein
Numb regulates levels of Notch receptor trafficking to Rab7-labeled late
endosomes but not early endosomes. Using an assay we developed that labels
different pools of Notch receptors as they move through the endocytic system, we
show that Numb specifically suppresses a recycled Notch receptor subpopulation
and that excess Notch signaling in numb mutants requires the recycling endosome
GTPase Rab11 activity. Our data therefore suggest that Numb controls the balance
between Notch receptor recycling and receptor targeting to late endosomes to
regulate signaling output after asymmetric cell division in Drosophila neural
progenitors. The correct establishment and maintece of unidirectional Notch signaling are
critical for the homeostasis of various stem cell lineages. However, the
molecular mechanisms that prevent cell-autonomous ectopic Notch signaling
activation and deleterious cell fate decisions remain unclear. Here we show that
the retromer complex directly and specifically regulates Notch receptor
retrograde trafficking in Drosophila neuroblast lineages to ensure the
unidirectional Notch signaling from neural progenitors to neuroblasts. Notch
polyubiquitination mediated by E3 ubiquitin ligase Itch/Su(dx) is inherently
inefficient within neural progenitors, relying on retromer-mediated trafficking
to avoid aberrant endosomal accumulation of Notch and cell-autonomous signaling
activation. Upon retromer dysfunction, hypo-ubiquitinated Notch accumulates in
Rab7+ enlarged endosomes, where it is ectopically processed and activated in a
ligand-dependent manner, causing progenitor-originated tumorigenesis. Our
results therefore unveil a safeguard mechanism whereby retromer retrieves
potentially harmful Notch receptors in a timely manner to prevent aberrant Notch
activation-induced neural progenitor dedifferentiation and brain tumor
formation. Neural stem cells divide during embryogenesis and juvenile life to generate the
entire complement of neurons and glia in the nervous system of vertebrates and
invertebrates. Studies of the mechanisms controlling the fine balance between
neural stem cells and more differentiated progenitors have shown that, in every
asymmetric cell division, progenitors send a Delta-Notch signal to their sibling
stem cells. Here, we show that excessive activation of Notch or overexpression
of its direct targets of the Hes family causes stem-cell hyperplasias in the
Drosophila larval central nervous system, which can progress to maligt
tumours after allografting to adult hosts. We combined transcriptomic data from
these hyperplasias with chromatin occupancy data for Dpn, a Hes transcription
factor, to identify genes regulated by Hes factors in this process. We show that
the Notch/Hes axis represses a cohort of transcription factor genes. These are
excluded from the stem cells and promote early differentiation steps, most
likely by preventing the reversion of immature progenitors to a stem-cell fate.
We describe the impact of two of these 'anti-stemness' factors, Zfh1 and Gcm, on
Notch/Hes-triggered tumorigenesis. |
In what clinical trials has SAR425899 been tested? | Subcutaneous administrations of SAR425899 were tested in two randomized, placebo-controlled, double-blind clinical trials. In the first trial, healthy overweight volunteers (body mass index [BMI] 25-30 kg/m2 ; n = 32) received single-ascending doses (0.01-0.1 mg) of SAR425899 or placebo. In the second, a multiple-ascending-dose trial (NCT02411825), healthy normal- to overweight volunteers (BMI 20-30 kg/m2 ; n = 40) and overweight/obese patients with T2D (BMI 28-42 kg/m2 ; n = 36) received daily doses of SAR425899 or placebo over 21 or 28 days, respectively. | AIMS: To evaluate the safety, pharmacokinetics and pharmacodynamics of
SAR425899, a novel polypeptide, active as an agonist at both the glucagon-like
peptide-1 receptor (GLP-1R) and the glucagon receptor (GCR), in healthy
volunteers and in overweight/obese patients with type 2 diabetes (T2D).
METHODS: Subcutaneous administrations of SAR425899 were tested in two
randomized, placebo-controlled, double-blind clinical trials. In the first
trial, healthy overweight volunteers (body mass index [BMI] 25-30 kg/m2 ;
n = 32) received single-ascending doses (0.01-0.1 mg) of SAR425899 or placebo.
In the second, a multiple-ascending-dose trial (NCT02411825), healthy normal- to
overweight volunteers (BMI 20-30 kg/m2 ; n = 40) and overweight/obese patients
with T2D (BMI 28-42 kg/m2 ; n = 36) received daily doses of SAR425899 or placebo
over 21 or 28 days, respectively.
RESULTS: The most frequently reported adverse events were gastrointestinal;
gastrointestinal side effects were less pronounced in patients with T2D compared
with healthy volunteers. SAR425899 significantly reduced levels of fasting
plasma glucose (P < 0.05 vs. placebo) and glycated haemoglobin (P < 0.001 versus
placebo) in patients with T2D. Additionally, SAR425899 led to reductions in body
weight, with a maximal reduction of 5.32 kg in healthy volunteers and 5.46 kg in
patients with T2D (P < 0.001 vs. placebo) at end of treatment.
CONCLUSIONS: SAR425899 was well tolerated and led to favourable glycaemic
effects in patients with T2D and weight reduction in both healthy volunteers and
patients. Whether dual GLP-1R/GCR agonism represents a treatment method that is
superior to pure GLP-1R agonists for obesity and diabetes treatment remains to
be confirmed. |
Is there a link between rare variants in PPARG and type 1 diabetes? | No. Rare variants in PPARG with decreased activity in adipocyte differentiation are associated with increased risk of type 2 diabetes. | |
What is the mechanisms of action of pexidartinib? | Pexidartinib is small-molecule tyrosine kinase inhibitor that has strong selectivity against colony-stimulating factor 1 receptor. | Background Pexidartinib, a novel, orally administered small-molecule tyrosine
kinase inhibitor, has strong selectivity against colony-stimulating factor 1
receptor. This phase I, nonrandomized, open-label multiple-dose study evaluated
pexidartinib safety and efficacy in Asian patients with symptomatic, advanced
solid tumors. Materials and Methods Patients received pexidartinib: cohort 1,
600 mg/d; cohort 2, 1000 mg/d for 2 weeks, then 800 mg/d. Primary objectives
assessed pexidartinib safety and tolerability, and determined the recommended
phase 2 dose; secondary objectives evaluated efficacy and pharmacokinetic
profile. Results All 11 patients (6 males, 5 females; median age 64, range
23-82; cohort 1 n = 3; cohort 2 n = 8) experienced at least one
treatment-emergent adverse event; 5 experienced at least one grade ≥ 3 adverse
event, most commonly (18%) for each of the following: increased aspartate
aminotransferase, blood alkaline phosphatase, gamma-glutamyl transferase, and
anemia. Recommended phase 2 dose was 1000 mg/d for 2 weeks and 800 mg/d
thereafter. Pexidartinib exposure, area under the plasma concentration-time
curve from zero to 8 h (AUC0-8h), and maximum observed plasma concentration
(Cmax) increased on days 1 and 15 with increasing pexidartinib doses, and time
at Cmax (Tmax) was consistent throughout all doses. Pexidartinib exposure and
plasma levels of adiponectin and colony-stimulating factor 1 increased following
multiple daily pexidartinib administrations. One patient (13%) with tenosynovial
giant cell tumor showed objective tumor response. Conclusions This was the first
study to evaluate pexidartinib in Asian patients with advanced solid tumors.
Pexidartinib was safe and tolerable in this population at the recommended phase
2 dose previously determined for Western patients (funded by Daiichi Sankyo;
clinicaltrials.gov number, NCT02734433). LESSONS LEARNED: The combination of pexidartinib and binimetinib was safe and
tolerable and demonstrated encouraging signs of efficacy in two patients with
advanced gastrointestinal stromal tumor (GIST) refractory to tyrosine kinase
inhibitors (TKIs).Molecular profiling of GISTs at diagnosis and upon progression
may provide insight into the mechanisms of response or resistance to targeted
therapies.Additional trials are needed to further explore combined KIT and MEK
inhibition in treatment-naïve and TKI-refractory patients with advanced GIST.
BACKGROUND: Nearly all patients with advanced gastrointestinal stromal tumor
(GIST) develop resistance to imatinib, and subsequent treatments have limited
efficacy. Dual inhibition of KIT and MAPK pathways has synergistic antitumor
activity in preclinical GIST models.
METHODS: This was an investigator-initiated, phase I, dose escalation study of
the MEK inhibitor binimetinib combined with pexidartinib, a potent inhibitor of
CSF1R, KIT, and FLT3, in patients with advanced or metastatic GIST who
progressed on imatinib. The primary endpoint was phase II dose determination;
secondary endpoints included safety, tolerability, and efficacy. An expansion
cohort to further evaluate safety and efficacy was planned.
RESULTS: Two patients were treated at dose level one (binimetinib 30 mg b.i.d.
and pexidartinib 400 mg every morning and 200 mg every evening), after which the
study was terminated by the manufacturer. No dose-limiting toxicities (DLTs)
were reported, and treatment was well tolerated. The only grade ≥3
treatment-emergent adverse event (TEAE) was asymptomatic elevated creatine
phosphokinase (CPK). Both patients had a best response of stable disease (SD) by
RECIST. Progression-free survival (PFS) and overall survival (OS) were 6.1 and
14.6 months, respectively, in one patient with five prior lines of therapy. The
second patient with NF1-mutant GIST had a 27% decrease in tumor burden by RECIST
and remains on study after 19 months of treatment.
CONCLUSION: Pexidartinib combined with binimetinib was tolerable, and meaningful
clinical activity was observed in two imatinib-refractory patients. BACKGROUND: Tenosynovial giant cell tumour (TGCT), a rare, locally aggressive
neoplasm, overexpresses colony-stimulating factor 1 (CSF1). Surgery is standard
with no approved systemic therapy. We aimed to evaluate pexidartinib, a CSF1
receptor inhibitor, in patients with TGCT to provide them with a viable systemic
treatment option, especially in cases that are not amenable to surgical
resection.
METHODS: This phase 3 randomised trial had two parts. Part one was a
double-blind study in which patients with symptomatic, advanced TGCT for whom
surgery was not recommended were randomly assigned via an integrated web
response system (1:1) to the pexidartinib or placebo group. Individuals in the
pexidartinib group received a loading dose of 1000 mg pexidartinib per day
orally (400 mg morning; 600 mg evening) for the first 2 weeks, followed by 800
mg per day (400 mg twice a day) for 22 weeks. Part two was an open-label study
of pexidartinib for all patients. The primary endpoint, assessed in all
intention-to-treat patients, was overall response at week 25, and was centrally
reviewed by RECIST, version 1.1. Safety was analysed in all patients who
received at least one dose of the study drug. This study is registered with
ClinicalTrials.gov, number NCT02371369.
FINDINGS: Between May 11, 2015, and Sept 30, 2016, of 174 patients assessed for
eligibility, 120 patients were randomly assigned to, and received, pexidartinib
(n=61) or placebo (n=59). There were 11 dropouts in the placebo group and nine
in the pexidartinib group. Emergence of mixed or cholestatic hepatotoxicity
caused the data monitoring committee to stop enrolment six patients short of
target. The proportion of patients who achieved overall response was higher for
pexidartinib than placebo at week 25 by RECIST (24 [39%] of 61 vs none of 59;
absolute difference 39% [95% CI 27-53]; p<0·0001). Serious adverse events
occurred in eight (13%) of 61 patients in the pexidartinib group and one (2%) of
59 patients in the placebo group. Hair colour changes (67%), fatigue (54%),
aspartate aminotransferase increase (39%), nausea (38%), alanine
aminotransferase increase (28%), and dysgeusia (25%) were the most frequent
pexidartinib-associated adverse events. Three patients given pexidartinib had
aminotransferase elevations three or more times the upper limit of normal with
total bilirubin and alkaline phosphatase two or more times the upper limit of
normal indicative of mixed or cholestatic hepatotoxicity, one lasting 7 months
and confirmed by biopsy.
INTERPRETATION: Pexidartinib is the first systemic therapy to show a robust
tumour response in TGCT with improved patient symptoms and functional outcomes;
mixed or cholestatic hepatotoxicity is an identified risk. Pexidartinib could be
considered as a potential treatment for TGCT associated with severe morbidity or
functional limitations in cases not amenable to improvement with surgery.
FUNDING: Daiichi Sankyo. Pexidartinib (PLX3397) is a small molecule tyrosine kinase and
colony-stimulating factor-1 inhibitor with FDA breakthrough therapy designation
for tenosynovial giant-cell tumor, and currently under study in several other
tumor types, including breast cancer, non-Hodgkin's lymphoma, and glioblastoma.
Here, we report a case of severe drug-induced liver injury requiring liver
transplantation due to vanishing bile duct syndrome (VBDS) after exposure to
pexidartinib in the I-SPY 2 Trial, a phase 2 multicenter randomized neoadjuvant
chemotherapy trial in patients with Stage II-III breast cancer. We also review
the current literature on this rare, idiosyncratic, and potentially
life-threatening entity. PURPOSE: To evaluate the safety, recommended phase II dose (RP2D) and efficacy
of pexidartinib, a colony stimulating factor receptor 1 (CSF-1R) inhibitor, in
combination with weekly paclitaxel in patients with advanced solid tumors.
PATIENTS AND METHODS: In part 1 of this phase Ib study, 24 patients with
advanced solid tumors received escalating doses of pexidartinib with weekly
paclitaxel (80 mg/m2). Pexidartinib was administered at 600 mg/day in cohort 1.
For subsequent cohorts, the dose was increased by ⩽50% using a standard 3+3
design. In part 2, 30 patients with metastatic solid tumors were enrolled to
examine safety, tolerability and efficacy of the RP2D. Pharmacokinetics and
biomarkers were also assessed.
RESULTS: A total of 51 patients reported ≥1 adverse event(s) (AEs) that were at
least possibly related to either study drug. Grade 3-4 AEs, including anemia
(26%), neutropenia (22%), lymphopenia (19%), fatigue (15%), and hypertension
(11%), were recorded in 38 patients (70%). In part 1, no maximum tolerated dose
was achieved and 1600 mg/day was determined to be the RP2D. Of 38 patients
evaluable for efficacy, 1 (3%) had complete response, 5 (13%) partial response,
13 (34%) stable disease, and 17 (45%) progressive disease. No drug-drug
interactions were found. Plasma CSF-1 levels increased 1.6- to 53-fold, and
CD14dim/CD16+ monocyte levels decreased by 57-100%.
CONCLUSIONS: The combination of pexidartinib and paclitaxel was generally well
tolerated. RP2D for pexidartinib was 1600 mg/day. Pexidartinib blocked CSF-1R
signaling, indicating potential for mitigating macrophage tumor infiltration. Pexidartinib (TURALIO™) is an orally administered small molecule tyrosine kinase
inhibitor with selective activity against the colony-stimulating factor 1 (CSF1)
receptor, KIT proto-oncogene receptor tyrosine kinase (KIT) and FMS-like
tyrosine kinase 3 harboring an internal tandem duplication mutation (FLT3-ITD).
In August 2019, the US FDA approved pexidartinib capsules for the treatment of
adult patients with symptomatic tenosynovial giant cell tumor (TGCT) associated
with severe morbidity or functional limitations and not amenable to improvement
with surgery. This approval was based on positive results from the phase III
ENLIVEN trial. Pexidartinib is being investigated in various maligcies as
monotherapy or combination therapy. This article summarizes the milestones in
the development of pexidartinib leading to its first approval for TGCT. Because genetic alterations including mutations, overexpression, translocations,
and dysregulation of protein kinases are involved in the pathogenesis of many
illnesses, this enzyme family is currently the subject of many drug discovery
programs in the pharmaceutical industry. The US FDA approved four small molecule
protein kinase antagonists in 2019; these include entrectinib, erdafitinib,
pexidartinib, and fedratinib. Entrectinib binds to TRKA/B/C and ROS1 and is
prescribed for the treatment of solid tumors with NTRK fusion proteins and for
ROS1-postive non-small cell lung cancers. Erdafitinib inhibits fibroblast growth
factor receptors 1-4 and is used in the treatment of urothelial bladder cancers.
Pexidartinib is a CSF1R antagonist that is prescribed for the treatment of
tenosynovial giant cell tumors. Fedratinib blocks JAK2 and is used in the
treatment of myelofibrosis. Overall, the US FDA has approved 52 small molecule
protein kinase inhibitors, nearly all of which are orally effective with the
exceptions of temsirolimus (which is given intravenously) and netarsudil (an eye
drop). Of the 52 approved drugs, eleven inhibit protein-serine/threonine protein
kinases, two are directed against dual specificity protein kinases, eleven
target non-receptor protein-tyrosine kinases, and 28 block receptor
protein-tyrosine kinases. The data indicate that 46 of these drugs are used in
the treatment of neoplastic diseases (eight against non-solid tumors such as
leukemias and 41 against solid tumors including breast and lung cancers; some
drugs are used against both tumor types). Eight drugs are employed in the
treatment of non-maligcies: fedratinib, myelofibrosis; ruxolitinib,
myelofibrosis and polycythemia vera; fostamatinib, chronic immune
thrombocytopenia; baricitinib, rheumatoid arthritis; sirolimus, renal graft vs.
host disease; nintedanib, idiopathic pulmonary fibrosis; netarsudil, glaucoma;
and tofacitinib, rheumatoid arthritis, Crohn disease, and ulcerative colitis.
Moreover, sirolimus and ibrutinib are used for the treatment of both neoplastic
and non-neoplastic diseases. Entrectinib and larotrectinib are tissue-agnostic
anti-cancer small molecule protein kinase inhibitors. These drugs are prescribed
for the treatment of any solid cancer harboring NTRK1/2/3 fusion proteins
regardless of the organ, tissue, anatomical location, or histology type. Of the
52 approved drugs, seventeen are used in the treatment of more than one disease.
Imatinib, for example, is approved for the treatment of eight disparate
disorders. The most common drug targets of the approved pharmaceuticals include
BCR-Abl, B-Raf, vascular endothelial growth factor receptors (VEGFR), epidermal
growth factor receptors (EGFR), and ALK. Most of the approved small molecule
protein kinase antagonists (49) bind to the protein kinase domain and six of
them bind covalently. In contrast, everolimus, temsirolimus, and sirolimus are
larger molecules (MW ≈ 1000) that bind to FK506 binding protein-12 (FKBP-12) to
generate a complex that inhibits the mammalian target of rapamycin (mTOR)
protein kinase complex. This review presents the physicochemical properties of
all of the FDA-approved small molecule protein kinase inhibitors. Twenty-two of
the 52 drugs have molecular weights greater than 500, exceeding a Lipinski rule
of five criterion. Excluding the macrolides (everolimus, sirolimus,
temsirolimus), the average molecular weight of the approved drugs is 480 with a
range of 306 (ruxolitinib) to 615 (trametinib). More than half of the
antagonists (29) have lipophilic efficiency values of less than five while the
recommended optima range from 5 to 10. One of the troublesome problems with both
targeted and cytotoxic drugs in the treatment of maligt diseases is the near
universal development of resistance to every therapeutic modality. Author information:
(1)Department of Pediatrics, University of Minnesota, United States of America;
Center for Genome Engineering, University of Minnesota, United States of
America; Masonic Cancer Center, University of Minnesota, United States of
America.
(2)Masonic Cancer Center, University of Minnesota, United States of America.
(3)Department of Pediatrics, University of Minnesota, United States of America.
(4)Department of Pediatrics, University of Minnesota, United States of America;
Center for Genome Engineering, University of Minnesota, United States of
America.
(5)Department of Pediatrics, University of Minnesota, United States of America;
Masonic Cancer Center, University of Minnesota, United States of America.
(6)Department of Pediatrics, University of Minnesota, United States of America;
Childhood Cancer Genomics Group, University of Minnesota, United States of
America.
(7)Cancer Research UK Cambridge Institute, University of Cambridge, United
Kingdom of Great Britain and Northern Ireland.
(8)Department of Pediatrics, University of Minnesota, United States of America;
Center for Genome Engineering, University of Minnesota, United States of
America; Masonic Cancer Center, University of Minnesota, United States of
America. Electronic address: [email protected].
(9)Department of Pediatrics, University of Minnesota, United States of America;
Department of Genetics, Cell Biology and Development, University of Minnesota,
United States of America; Center for Genome Engineering, University of
Minnesota, United States of America; Masonic Cancer Center, University of
Minnesota, United States of America. Electronic address: [email protected]. PURPOSE: Pexidartinib (PLX3397) is a colony-stimulating factor-1 receptor
(CSF-1R) inhibitor under clinical evaluation for potential CNS tumor treatment.
This study aims to evaluate plasma pharmacokinetic parameters and estimate CNS
penetrance of pexidartinib in a non-human primate (NHP) cerebrospinal fluid
(CSF) reservoir model.
METHODS: Five male rhesus macaques, each with a previously implanted
subcutaneous CSF ventricular reservoir and central venous lines, were used. NHPs
received a single dose of 40 mg/kg pexidartinib (human equivalent dose of
800 mg/m2), administered orally as 200 mg tablets. Serial paired samples of
blood and CSF were collected at 0-8, 24, 48, and 72 h. Pexidartinib
concentrations were assayed by Integrated Analytical Solutions, Inc. (Berkeley,
CA, USA) using HPLC/MS/MS. Pharmacokinetic (PK) analysis was performed using
noncompartmental methods.
RESULTS: Samples from four NHPs were evaluable. Average (± SD) plasma PK
parameters were as follows: Cmax = 16.50 (± 6.67) μg/mL; Tmax = 5.00 (± 2.58) h;
AUClast = 250.25 (± 103.76) h*μg/mL; CL = 0.18 (± 0.10) L/h/kg. In CSF,
pexidartinib was either quantifiable (n = 2), with Cmax values of 16.1 and
10.1 ng/mL achieved 2-4 h after plasma Tmax, or undetected at all time points
(n = 2, LLOQCSF = 5 ng/mL).
CONCLUSION: Pexidartinib was well-tolerated in NHPs, with no Grade 3 or Grade 4
toxicities. The CSF penetration of pexidartinib after single-dose oral
administration to NHPs was limited. Tenosynovial giant cell tumor (TGCT) is a rare benign tumor that involves the
synovium, bursa, and tendon sheath, resulting in reduced mobility of the
affected joint or limb. The current standard of care for TGCT is surgical
resection. However, some patients have tumor recurrence, present with
unresectable tumors, or have tumors that are in locations where resection could
result in amputations or significant debility. Therefore, the development of
systemic agents with activity against TGCT to expand treatment options is a
highly unmet medical need. Pathologically, TGCT is characterized by the
overexpression of colony-stimulating factor 1 (CSF-1), which leads to the
recruitment of colony-stimulating factor-1 receptor (CSF-1R) expressing
macrophages that make up the primary cell type within these giant cell tumors.
The binding of CSF-1 and CSF-1R controls cell survival and proliferation of
monocytes and the switch from a monocytic to macrophage phenotype contributing
to the growth and inflammation within these tumors. Therefore, molecules that
target CSF-1/CSF-1R have emerged as potential systemic agents for the treatment
of TGCT. Given the role of macrophages in regulating tumorigenesis,
CSF1/CSF1R-targeting agents have emerged as attractive therapeutic targets for
solid tumors. Pexidartinib is an orally bioavailable and potent inhibitor of
CSF-1R which is one of the most clinically used agents. In this review, we
discuss the biology of TGCT and review the pre-clinical and clinical development
of pexidartinib which ultimately led to the FDA approval of this agent for the
treatment of TGCT as well as ongoing clinical studies utilizing pexidartinib in
the setting of cancer. Kusunokinin, a lig compound, inhibits cancer cell proliferation and induces
apoptosis; however, the role of kusunokinin is not fully understood. Here, we
aimed to identify a target protein of (-)-kusunokinin and determine the protein
levels of its downstream molecules. We found that (-)-kusunokinin bound 5
possible target proteins, including CSF1R, MMP-12, HSP90-α, CyclinB1 and MEK1
with ΔGbind less than -10.40 kcal/mol. MD simulation indicated (-)-kusunokinin
and pexidartinib (P31, a specific CSF1R binding compound) shared some extents of
functional similarity in which (-)-kusunokinin bound CSF1R at the juxtamembrane
(JM) region with aromatic amino acids similar to pexidartinib using π-π
interaction, as well as hydrogen bond. Both P31 and (-)-kusunokinin moved into
the same CSF1R region and W7 was a mutual key residue. However, the P31 binding
site differed from the (-)-kusunokinin binding site. For in vitro study, the
synthetic (±)-kusunokinin exhibited stronger cytotoxicity than
picropodophyllotoxin, silibinin and etoposide on MCF-7 cells and represented
less toxicity than picropodophyllotoxin and doxorubicin on L-929 and MCF-12A
cells. Knocking down CSF1R using a specific siRNA combination with
(±)-kusunokinin demonstrated levels of cell proliferation proteins slightly
higher than siRNA-CSF1R treatment. However, siRNA-CSF1R combination with P31
represented the number of cell viability and cell proliferation proteins, like
in the control groups (Lipofectamine and siRNA-Luciferase). Moreover,
(±)-kusunokinin suppressed CSF1R and its downstream proteins, including AKT,
CyclinD1 and CDK1. Meanwhile, both P31 and siRNA-CSF1R dramatically suppressed
CSF1R, MEK1, AKT, ERK, CyclinB1, CyclinD1 and CDK1. Our overall results indicate
that the mechanism of (±)-kusunokinin differed fairly from P31. We have
concluded that (±)-kusunokinin inhibited breast cancer cell proliferation
partially through the binding and suppression of CSF1R, which consequently
affected AKT and its downstream molecules. PURPOSE: Simultaneously targeting the tumor and tumor microenvironment may hold
promise in treating children with refractory solid tumors. Pexidartinib, an oral
inhibitor of tyrosine kinases including colony stimulating factor 1 receptor
(CSF-1R), KIT, and FLT3, is FDA approved in adults with tenosynovial giant cell
tumor. A phase I trial was conducted in pediatric and young adult patients with
refractory leukemias or solid tumors including neurofibromatosis type 1-related
plexiform neurofibromas.
PATIENTS AND METHODS: A rolling six design with dose levels (DL) of 400 mg/m2,
600 mg/m2, and 800 mg/m2 once daily for 28-day cycles (C) was used. Response was
assessed at regular intervals. Pharmacokinetics and population pharmacokinetics
were analyzed during C1.
RESULTS: Twelve patients (4 per DL, 9 evaluable) enrolled on the dose-escalation
phase and 4 patients enrolled in the expansion cohort: median (lower, upper
quartile) age 16 (14, 16.5) years. No dose-limiting toxicities were observed.
Pharmacokinetics appeared linear over three DLs. Pharmacokinetic modeling and
simulation determined a weight-based recommended phase II dose (RP2D). Two
patients had stable disease and 1 patient with peritoneal mesothelioma (C49+)
had a sustained partial response (67% RECIST reduction). Pharmacodynamic markers
included a rise in plasma macrophage CSF (MCSF) levels and a decrease in
absolute monocyte count.
CONCLUSIONS: Pexidartinib in pediatric patients was well tolerated at all DL
tested, achieved target inhibition, and resulted in a weight-based RPD2 dose. |
List pore forming toxins. | cytolysin A
α-hemolysin
Streptolysin O
pneumolysin
listeriolysin
leukocidin
Glabralysin | Host-pathogen interactions are central to understanding microbial pathogenesis.
The staphylococcal pore-forming cytotoxins hijack important immune molecules but
little is known about the underlying molecular mechanisms of cytotoxin-receptor
interaction and host specificity. Here we report the structures of a
staphylococcal pore-forming cytotoxin, leukocidin GH (LukGH), in complex with
its receptor (the α-I domain of complement receptor 3, CD11b-I), both for the
human and murine homologs. We observe 2 binding interfaces, on the LukG and the
LukH protomers, and show that human CD11b-I induces LukGH oligomerization in
solution. LukGH binds murine CD11b-I weakly and is inactive toward murine
neutrophils. Using a LukGH variant engineered to bind mouse CD11b-I, we
demonstrate that cytolytic activity does not only require binding but also
receptor-dependent oligomerization. Our studies provide an unprecedented insight
into bicomponent leukocidin-host receptor interaction, enabling the development
of antitoxin approaches and improved animal models to explore these approaches. Pore forming toxins (PFTs) are proteins which form unregulated oligomeric pores
on target plasma membranes to cause ion leakage and cell death and represent the
largest class of bacterial virulence factors. With increasing
antibiotic-resistant bacterial strains, alternate therapies are being developed
to target toxin pore formation rather than the bacteria themselves. One strategy
is to undermine the stability of these multimeric pores, whose subunits are held
together by complex amino acid interaction networks, by identifying key residues
in these networks which could be plausible drug or mutagenesis targets. However,
this requires a quantitative assessment of per residue contributions towards
pore stability, which cannot be reliably gleaned from static crystal/cryo-EM
pore structures. In this study, we overcome this limitation by developing a
computational screening algorithm that employs fully atomistic molecular
dynamics simulations coupled with energy-based screening that can predict
'hot-spot' residues which engage in persistent and stabilizing hydrogen bonds or
salt bridges across protein-protein interfaces. Application of this algorithm to
prototypical α-PFT (cytolysin A) and β-PFT (α-hemolysin) membrane-inserted pores
yielded a small predicted set of highly interacting residues, blocking of which
could destabilize pore complexes. Previous mutagenesis studies validate some of
our in silico predictions. The algorithm could be applied to all pores with
known structures to generate a database of destabilizing mutations, which could
then serve as a basis for experimental validation and rational structure-based
inhibitor design.Communicated by Ramaswamy H. Sarma. Biomphalaria glabrata is a freshwater Planorbidae snail. In its environment,
this mollusk faces numerous microorganisms or pathogens, and has developed
sophisticated innate immune mechanisms to survive. The mechanisms of recognition
are quite well understood in Biomphalaria glabrata, but immune effectors have
been seldom described. In this study, we analyzed a new family of potential
immune effectors and characterized five new genes that were named Glabralysins.
The five Glabralysin genes showed different genomic structures and the high
degree of amino acid identity between the Glabralysins, and the presence of the
conserved ETX/MTX2 domain, support the hypothesis that they are pore-forming
toxins. In addition, tertiary structure prediction confirms that they are
structurally related to a subset of Cry toxins from Bacillus thuringiensis,
including Cry23, Cry45, and Cry51. Finally, we investigated their gene
expression profiles in snail tissues and demonstrated a mosaic transcription. We
highlight the specificity in Glabralysin expression following immune stimulation
with bacteria, yeast or trematode parasites. Interestingly, one Glabralysin was
found to be expressed in immune-specialized hemocytes, and two others were
induced following parasite exposure. Staphylococcal bi-component pore-forming toxins, also known as leukocidins,
target and lyse human phagocytes in a receptor-dependent manner. S-components of
the leukocidins Panton-Valentine leukocidin (PVL), γ-haemolysin AB (HlgAB) and
CB (HlgCB), and leukocidin ED (LukED) specifically employ receptors that belong
to the class of G-protein coupled receptors (GPCRs). Although these receptors
share a common structural architecture, little is known about the conserved
characteristics of the interaction between leukocidins and GPCRs. In this study,
we investigated host cellular pathways contributing to susceptibility towards S.
aureus leukocidin cytotoxicity. We performed a genome-wide CRISPR/Cas9 library
screen for toxin-resistance in U937 cells sensitized to leukocidins by ectopic
expression of different GPCRs. Our screen identifies post-translational
modification (PTM) pathways involved in the sulfation and sialylation of the
leukocidin-receptors. Subsequent validation experiments show differences in the
impact of PTM moieties on leukocidin toxicity, highlighting an additional layer
of refinement and divergence in the staphylococcal host-pathogen interface.
Leukocidin receptors may serve as targets for anti-staphylococcal interventions
and understanding toxin-receptor interactions will facilitate the development of
innovative therapeutics. Variations in the genes encoding PTM pathways could
provide insight into observed differences in susceptibility of humans to
infections with S. aureus. |
What syndrome is associated with mutations in lysine methyltransferase 2D KMT2D? | Mutations in lysine methyltransferase 2D (KMT2D) gene, which encodes the catalytic core of a multisubunit chromatin remodeling enzyme, are responsible for the neurodegenerative disorder Kabuki syndrome. | CHARGE syndrome is a complex developmental disorder caused by mutations in the
chromodomain helicase DNA-binding gene CHD7. Kabuki syndrome, another
developmental disorder, is characterized by typical facial features in
combination with developmental delay, short stature, prominent digit pads and
visceral abnormalities. Mutations in the KMT2D gene, which encodes a H3K4
histone methyltransferase, are the major cause of Kabuki syndrome. Here, we
report a patient, who was initially diagnosed with CHARGE syndrome based on the
spectrum of inner organ malformations like choanal hypoplasia, heart defect,
anal atresia, vision problems and conductive hearing impairment. While
sequencing and MLPA analysis of all coding exons of CHD7 revealed no pathogenic
mutation, sequence analysis of the KMT2D gene identified the heterozygous de
novo nonsense mutation c.5263C > T (p.Gln1755*). Thus, our patient was diagnosed
with Kabuki syndrome. By using co-immunoprecipitation, immunohistochemistry and
direct yeast two hybrid assays, we could show that, like KMT2D, CHD7 interacts
with members of the WAR complex, namely WDR5, ASH2L and RbBP5. We therefore
propose that CHD7 and KMT2D function in the same chromatin modification
machinery, thus pointing out a mechanistic connection, and presenting a probable
explanation for the phenotypic overlap between Kabuki and CHARGE syndromes. KBG syndrome is a rare, autosomal domit disorder caused by mutations or
deletions leading to haploinsufficiency for the Ankrin Repeating
Domain-Containing protein 11 (ANKRD11) at chromosome 16q24.3. Kabuki syndrome is
caused by mutations or deletions of lysine (K)-specific methyltransferase 2D
(KMT2D) and lysine-specific methylase 6A (KDM6A). We report on a male with
developmental delays, cleft palate, craniofacial dysmorphism, hypotonia, and
central nervous system anomalies including diminished white matter with thinning
of the corpus callosum. Exome sequencing revealed a de novo mutation in ANKRD11,
c.2606_2608delAGA, predicting p.Lys869del and an additional, de novo mutation,
c.2353T>C, predicting p.Tyr785His in KDM1A, a gene not previously associated
with a human phenotype. We describe this child as the first report of a
deleterious sequence variant in KDM1A and hypothesize that his phenotype
resulted from the combined effect of both mutations. Author information:
(1)Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158, USA
Roddenberry Center for Stem Cell Biology and Medicine at Gladstone, San
Francisco, CA 94158, USA Biomedical Sciences Graduate Program, University of
California, San Francisco, San Francisco, CA 94158, USA.
(2)Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158, USA
Roddenberry Center for Stem Cell Biology and Medicine at Gladstone, San
Francisco, CA 94158, USA.
(3)National Institute of Diabetes and Digestive and Kidney Diseases, National
Institutes of Health, Bethesda, MD 20892, USA.
(4)Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158, USA
Roddenberry Center for Stem Cell Biology and Medicine at Gladstone, San
Francisco, CA 94158, USA Biomedical Sciences Graduate Program, University of
California, San Francisco, San Francisco, CA 94158, USA Cardiovascular Research
Institute, University of California, San Francisco, San Francisco, CA 94143, USA
Department of Pediatrics, University of California, San Francisco, San
Francisco, CA 94143, USA [email protected]. Kabuki syndrome (KS) is a rare genetic syndrome characterized by multiple
congenital anomalies and varying degrees of mental retardation. Patients with KS
often present with facial, skeletal, visceral and dermatoglyphic abnormalities,
cardiac anomalies and immunological defects. Mutation of the lysine
methyltransferase 2D (KMT2D) gene (formerly known as MLL2) is the primary cause
of KS. The present study reported the case of a 4‑year‑old Chinese girl who
presented with atypical KS, including atypical facial features, unclear speech
and suspected mental retardation. A diagnosis of KS was confirmed by genetic
testing, which revealed a nonsense mutation in exon 16 of KMT2D (c.4485C>A,
Tyr1495Ter). To the best of our knowledge, this is a novel mutation that has not
been reported previously. The present case underscores the importance of genetic
testing in KS diagnosis. INTRODUCTION: SCLC is a lethal neuroendocrine tumor type that is highly prone to
metastasis. There is an urgency to understand the mutated genes that promote
SCLC, as there are no approved targeted therapies yet available. SCLC is rarely
resected, limiting the number of samples available for genomic analyses of
somatic mutations.
METHODS: To identify potential driver mutations in human SCLC we sequenced the
whole exomes of 18 primary SCLCs and seven cell lines along with matched normal
controls. We extended these data by resequencing a panel of genes across 40
primary SCLCs and 48 cell lines.
RESULTS: We report frequent mutations in the lysine methyltransferase 2D gene
(KMT2D) (also known as MLL2), a key regulator of transcriptional enhancer
function. KMT2D exhibited truncating nonsense/frameshift/splice site mutations
in 8% of SCLC tumors and 17% of SCLC cell lines. We found that KMT2D mutation in
human SCLC cell lines was associated with reduced lysine methyltransferase 2D
protein levels and reduced monomethylation of histone H3 lysine 4, a mark
associated with transcriptional enhancers. We also found mutations in other
genes associated with transcriptional enhancer control, including CREB binding
protein gene (CREBBP), E1A binding protein p300 gene (EP300), and chromodomain
helicase DNA binding protein 7 gene (CHD7), and we report mutations in
additional chromatin remodeling genes such as polybromo 1 gene (PBRM1).
CONCLUSIONS: These data indicate that KMT2D is one of the major mutated genes in
SCLC, and they point to perturbation of transcriptional enhancer control as
potentially contributing to SCLC. Author information:
(1)Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario
M5G 1X8, Canada.
(2)Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario
M5G 1X8, Canada; Division of Clinical and Metabolic Genetics, The Hospital for
Sick Children, Toronto, Ontario M5G 1X8, Canada; Department of Molecular
Genetics, University of Toronto, Toronto, Ontario, M5S 1A1, Canada.
(3)Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario
M5G 1X8, Canada; Centre for Computational Medicine, The Hospital for Sick
Children, Toronto, Ontario M5G 1X8, Canada.
(4)Division of Clinical and Metabolic Genetics, The Hospital for Sick Children,
Toronto, Ontario M5G 1X8, Canada; Department of Pediatrics, University of
Toronto, Toronto, Ontario, M5S 1A1, Canada.
(5)Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario
M5G 1X8, Canada; Division of Clinical and Metabolic Genetics, The Hospital for
Sick Children, Toronto, Ontario M5G 1X8, Canada; Department of Pediatrics,
University of Toronto, Toronto, Ontario, M5S 1A1, Canada.
(6)Division of Clinical and Metabolic Genetics, The Hospital for Sick Children,
Toronto, Ontario M5G 1X8, Canada; Department of Molecular Genetics, University
of Toronto, Toronto, Ontario, M5S 1A1, Canada; Department of Pediatrics,
University of Toronto, Toronto, Ontario, M5S 1A1, Canada; Prenatal Diagnosis and
Medical Genetics Program, Mount Sinai Hospital, Toronto, Ontario, M5G 1X5,
Canada.
(7)Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario
M5G 1X8, Canada; The Centre for Applied Genomics, The Hospital for Sick
Children, Toronto, Ontario M5G 1X8 Canada.
(8)PreventionGenetics, Marshfield, WI, 54449, USA.
(9)Department of Medical Genetics, University of Alberta, Edmonton, Alberta, T6G
2R3, Canada.
(10)Division of Clinical and Metabolic Genetics, The Hospital for Sick Children,
Toronto, Ontario M5G 1X8, Canada.
(11)Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario,
L8S 4L8, Canada.
(12)National Centre for Medical Genetics, Our Lady's Children's Hospital,
Crumlin, Dublin 12, Ireland.
(13)Service de Génétique, Centre de Référence Anomalies du Développement de
l'Ouest, CHU Poitiers, 86021 Poitiers, France; EA3808, Université de Poitiers,
France.
(14)Département de Génétique, APHP-Hôpital Robert DEBRE, 75019 Paris, France.
(15)Center for Human Genetics Inc., Cambridge, MA 02139, USA.
(16)Paediatric Laboratory Medicine, The Hospital for Sick Children, Toronto,
Ontario M5G 1X8 Canada; Laboratory Medicine and Pathobiology, University of
Toronto, Toronto, Ontario, M5S 1A1, Canada.
(17)Otolaryngology, The Hospital for Sick Children, Toronto, Ontario M5G 1X8,
Canada; Department of Otolaryngology, University of Toronto, Toronto, Ontario,
M5S 1A1, Canada; Institute of Medical Sciences, University of Toronto, Toronto,
Ontario M5S 1A8, Canada.
(18)Laboratory Medicine and Pathobiology, University of Toronto, Toronto,
Ontario, M5S 1A1, Canada; Genome Diagnostics, Department of Clinical Laboratory
Genetics, University Health Network, Canada.
(19)Genetics and Genome Biology, The Hospital for Sick Children, Toronto,
Ontario M5G 1X8, Canada; Department of Molecular Genetics, University of
Toronto, Toronto, Ontario, M5S 1A1, Canada; The Centre for Applied Genomics, The
Hospital for Sick Children, Toronto, Ontario M5G 1X8 Canada; McLaughlin Centre,
University of Toronto, Toronto, Ontario, M5S 1A1, Canada.
(20)Genetics and Genome Biology, The Hospital for Sick Children, Toronto,
Ontario M5G 1X8, Canada; Centre for Computational Medicine, The Hospital for
Sick Children, Toronto, Ontario M5G 1X8, Canada; Department of Computer Science,
University of Toronto, Toronto, Ontario, M5S 1A1, Canada.
(21)Genetics and Genome Biology, The Hospital for Sick Children, Toronto,
Ontario M5G 1X8, Canada; Division of Clinical and Metabolic Genetics, The
Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada; Department of
Molecular Genetics, University of Toronto, Toronto, Ontario, M5S 1A1, Canada;
Department of Pediatrics, University of Toronto, Toronto, Ontario, M5S 1A1,
Canada; Institute of Medical Sciences, University of Toronto, Toronto, Ontario
M5S 1A8, Canada. Electronic address: [email protected]. BACKGROUND: Kabuki syndrome is characterized by distinctive facial features and
varying degrees of growth retardation. It leads to malformations in skeletal,
urogenital and cardiac structures; moreover, endocrine conditions such as
premature thelarche, precocious puberty, growth hormone deficiency, diabetes
insipidus, thyroid dysfunction and obesity have been reported. Kabuki syndrome
is caused by a heterozygous mutation in the KMT2D or KDM6A genes.
CASE PRESENTATION: An 11-year-old girl with the typical facial features of
Kabuki syndrome visited our hospital due to her short stature. She was found to
have the de novo heterozygous mutation of c.8200C > T, p(Arg2734*) in exon 32 of
the KMT2D gene and was diagnosed with Kabuki syndrome. The patient also
exhibited endocrine abnormalities such as a constitutional delay of puberty,
transiently congenial hypothyroidism, obesity and growth hormone deficiency.
CONCLUSIONS: This is a case of a mutation in the KMT2D gene in a girl with
Kabuki syndrome who presented with endocrine symptoms (constitutional delay of
puberty, hypothyroidism, obesity and growth hormone deficiency). The recessive mutant mice bate palmas (bapa) - claps in Portuguese arose from
N-ethyl-N-nitrosourea mutagenesis. A single nucleotide, T > C, change in exon
13, leading to a Thr1289 Ala substitution, was identified in the lysine
(K)-specific methyltransferase 2D gene (Kmt2d) located on chromosome 15.
Mutations with a loss-of-function in the KMT2D gene on chromosome 12 in humans
are responsible for Kabuki syndrome (KS). Phenotypic characterization of the
bapa mutant was performed using a behavioral test battery to evaluate the
parameters related to general activity, the sensory nervous system, the
psychomotor system, and the autonomous nervous system, as well as to measure
motor function and spatial memory. Relative to BALB/cJ mice, the bapa mutant
showed sensory and psychomotor impairments, such as hypotonia denoted by a
surface righting reflex impairment and hindquarter fall, and a reduction in the
auricular reflex, suggesting hearing impairment. Additionally, the enhanced
general activity showed by the increased rearing and grooming frequency,
distance traveled and average speed possibly presupposes the presence of
hyperactivity of bapa mice compared with the control group. A slight motor
coordination dysfunction was showed in bapa mice, which had a longer crossing
time on the balance beam compared with BALB/cJ controls. Male bapa mice also
showed spatial gait pattern changes, such as a shorter stride length and shorter
step length. In conclusion, the bapa mouse may be a valuable animal model to
study the mechanisms involved in psychomotor and behavior impairments, such as
hypotonia, fine motor coordination and hyperactivity linked to the Kmt2d
mutation. BACKGROUND: Kabuki syndrome is a haploinsufficient congenital multi-organ
malformation syndrome, which frequently includes severe heart defects. Mutations
in the histone H3K4 methyltransferase KMT2D have been identified as the main
cause of Kabuki syndrome, however, the role of KMT2D in heart development
remains to be characterized.
RESULTS: Here we analyze the function of Kmt2d at different stages of Xenopus
heart development. Xenopus Kmt2d is ubiquitously expressed at early stages of
cardiogenesis, with enrichment in the anterior region including the cardiac
precursor cells. Morpholino-mediated knockdown of Kmt2d led to hypoplastic
hearts lacking the three-chambered structure. Analyzing different stages of
cardiogenesis revealed that development of the first and second heart fields as
well as cardiac differentiation were severely affected by loss of Kmt2d
function.
CONCLUSION: Kmt2d loss of function in Xenopus recapitulates the hypoplastic
heart defects observed in Kabuki syndrome patients and shows that Kmt2d function
is required for the establishment of the primary and secondary heart fields.
Thus, Xenopus Kmt2d morphants can be a valuable tool to elucidate the etiology
of the congenital heart defects associated with Kabuki syndrome. Lysine methyltransferase 2D (KMT2D; OMIM 602113) encodes a histone
methyltransferase involved in transcriptional regulation of the beta-globin and
estrogen receptor as part of a large protein complex known as activating signal
cointegrator-2-containing complex (ASCOM). Heterozygous germline mutations in
the KMT2D gene are known to cause Kabuki syndrome (OMIM 147920), a developmental
multisystem disorder. Neither holoprosencephaly nor other defects in human
forebrain development have been previously associated with Kabuki syndrome. Here
we report two patients diagnosed with alobar holoprosencephaly in their
antenatal period with de novo monoallelic KMT2D variants identified by
trio-based exome sequencing. The first patient was found to have a stop-gain
variant c.12565G>T (p.Gly4189*), while the second patient had a missense variant
c.5A>G (p.Asp2Gly). Phenotyping of each patient did not reveal any age-related
feature of Kabuki syndrome. These two cases represent the first report on
association between KMT2D and holoprosencephaly. Chromatin modifiers act to coordinate gene expression changes critical to
neuronal differentiation from neural stem/progenitor cells (NSPCs).
Lysine-specific methyltransferase 2D (KMT2D) encodes a histone methyltransferase
that promotes transcriptional activation and is frequently mutated in cancers
and in the majority (>70%) of patients diagnosed with the congenital,
multisystem intellectual disability disorder Kabuki syndrome 1 (KS1). Critical
roles for KMT2D are established in various non-neural tissues, but the effects
of KMT2D loss in brain cell development have not been described. We conducted
parallel studies of proliferation, differentiation, transcription, and chromatin
profiling in KMT2D-deficient human and mouse models to define KMT2D-regulated
functions in neurodevelopmental contexts, including adult-born hippocampal NSPCs
in vivo and in vitro. We report cell-autonomous defects in proliferation, cell
cycle, and survival, accompanied by early NSPC maturation in several
KMT2D-deficient model systems. Transcriptional suppression in KMT2D-deficient
cells indicated strong perturbation of hypoxia-responsive metabolism pathways.
Functional experiments confirmed abnormalities of cellular hypoxia responses in
KMT2D-deficient neural cells and accelerated NSPC maturation in vivo. Together,
our findings support a model in which loss of KMT2D function suppresses
expression of oxygen-responsive gene programs important to neural progenitor
maintece, resulting in precocious neuronal differentiation in a mouse model
of KS1. Kabuki syndrome (KS) is a rare congenital disorder characterized by distinctive
facies, postnatal growth deficiency, cardiac defects and skeletal anomalies.
Studies have determined that pathogenic variants of the lysine-specific
methyltransferase 2D (KMT2D) and lysine-specific demethylase 6A (KDM6A) genes
are the major causes of KS. The two genes encode different histone-modifying
enzymes that are found in the same protein complex that is critical for cell
differentiation during development. Here we report the results from
next-generation sequencing of genomic DNA from 13 patients who had a clinical
diagnosis of KS based on facial dysmorphism and other KS-specific cardinal
phenotypes. Nine of the 13 patients were confirmed to be carrying heterozygous
pathogenic KMT2D variants, seven of which were truncating and two were missense
substitutions. Overall, we uncovered 11 novel variants - nine in KMT2D and two
in KDM6A. Seven of the novel variants (all KMT2D) were likely causative of the
KS phenotype. Our study expands the number of naturally occurring KMT2D and
KDM6A variants. The discovery of novel pathogenic variants will add to the
knowledge on disease-causing variants and the relevance of missense variants in
KS. Author information:
(1)Division of Medical Genetics, Kanagawa Children's Medical Center, Yokohama,
Japan.
(2)Clinical Research Institute, Kanagawa Children's Medical Center, Yokohama,
Japan.
(3)Division of Hematology/Oncology, Kanagawa Children's Medical Center,
Yokohama, Japan.
(4)Department of Clinical Laboratory, Kanagawa Children's Medical Center,
Yokohama, Japan.
(5)Department of Medical Genetics and Genomics, Sapporo Medical University
School of Medicine, Sapporo, Japan.
(6)Graduate School of Medicine, Tohoku University, Sendai, Japan.
(7)Division of Medical Genetics, Gunma Children's Medical Center, Gunma, Japan.
(8)Department of Pediatrics, Jikei University School of Medicine, Tokyo, Japan.
(9)Children's Medical Center, Northern Yokohama Hospital, Showa University,
Yokohama, Japan.
(10)Division of Clinical Genetics and Cytogenetics, Shizuoka Children's
Hospital, Shizuoka, Japan.
(11)Tanaka Growth Clinic, Tokyo, Japan.
(12)Department of Pediatrics, Dokkyo Medical University, Tochigi, Japan.
(13)Department of Clinical Genetics, Kurashiki Central Hospital, Kurashiki,
Japan.
(14)Department of Gynecology, Shikoku Medical Center for Children and Adults,
Kagawa, Japan.
(15)Department of Genome Medicine, National Center for Child Health and
Development, Tokyo, Japan.
(16)Center for Medical Genetics, Keio University School of Medicine, Tokyo,
Japan.
(17)Genetic Counseling Program, Graduate School of Health and Welfare, Kawasaki
University of Medical Welfare, Kurashiki, Japan. |
Does steroid 5A-Reductase deficiency lead to hermaphroditism? | Yes, steroid 5A-reductase deficiency can lead to hermaphroditism. | During a 10-year period 65 children and adolescents with ambiguous genitalia
from the Dominican Republic, not known through kindred studies of 5
alpha-reductase deficiency, were evaluated. Plasma androgen determinations were
performed before and/or after Leydig cell stimulation of the testes with human
chorionic gonadotropin. Of the children there were 24 female
pseudohermaphrodites, 21 of whom had 21-hydroxylase deficiency, 1 true
hermaphrodite and 40 (62 per cent) male pseudohermaphrodites. One child had a
human chorionic gonadotropin response suggestive of 17-20 desmolase deficiency,
and on further evaluation he also had partial deficiencies of the enzymes
21-hydroxylase and 17 alpha-hydroxylase. Five subjects had a female phenotype
and subnormal androgen responses to human chorionic gonadotropin. In 5 of 33
male pseudohermaphrodites with a normal testosterone response to human chorionic
gonadotropin 5 alpha-reductase deficiency was suspected by elevated plasma
testosterone/dihydrotestosterone ratios before and/or after human chorionic
gonadotropin stimulation. The diagnosis of 5 alpha-reductase deficiency was
confirmed by elevated 5 beta/5 alpha urinary C19 and C21 steroid metabolite
ratios. One subject with 5 alpha-reductase deficiency was traced to the original
Dominican kindred of 38 affected subjects. Pedigree analysis of another proband
revealed 3 additional affected relatives. Four subjects with a normal
testosterone response to human chorionic gonadotropin had XO/XY gonadal
dysgenesis. There were 25 male pseudohermaphrodites with normal plasma
testosterone and dihydrotestosterone responses to human chorionic gonadotropin,
who were not diagnosed by this methodology. This study reveals that 5
alpha-reductase deficiency occurs with a frequency of 13 per cent as a cause of
male pseudohermaphroditism in the Dominican Republic with approximately the same
frequency as XO/XY gonadal dysgenesis. Unlike female pseudohermaphrodites, the
majority of male subjects with pseudohermaphroditism remain unclassified by
these techniques. The deficiency of steroid 5 alpha-reductase leads to the disturbances in sex
differentiation that cause symptoms of male pseudohermaphroditism. The methods
of DNA analysis used to diagnose mutations of steroid 5 alpha-reductase gene
(SRD5A2) were presented and discussed. Within the group of 21 patients with the
deficiency of steroid 5 alpha-reductase 2 described so far in literature, the
analysis of SRD5A2 gene revealed two "major" deletions, one "minor" deletion, 16
point mutations (incl. 5 transitions and 11 transversions), in one case a
mutation causing premature termination of translation and in one case mutation
leading to defective splicing of the mRNA. The mutations localized in exons 2
and 5 cause a decrease in affinity of 5 alpha-reductase 2 to the substrate
(testosterone), while the mutations in exons 1 and 4, a decrease in affinity to
the coenzyme (NADPH). Contrary to what is observed in true hermaphroditism and in male
pseudo-hermaphroditism, there is no erroneous transmission of the genetic
gonadal differentiation programme in female pseudohermaphroditism. All that has
happened is virilization of the urogenital sinus and external genitalia in a
foetus exposed to exo- or endogenous androgens. In the absence of testis there
is no production of anti-mullerian hormone, and for these reasons the uterus,
the fallopian tubes and the vagina develop normally, whilst the wollfian ducts
are regressed and there is no trace of male deep spermatic pathway. On the basis
of recent acquisitions in biochemistry, endocrinology and embryogenesis, the
authors compare the various degrees of virilization with the biochemical
abnormalities. Male pseudohermaphroditism caused by steroid 5alpha-reductase deficiency is an
autosomal recessive disorder. The enzyme steroid 5alpha-reductase 2 (encoded by
the SRD5A2 gene) catalyses the conversion of testosterone to
dihydrotestosterone, which is required for normal differentiation of the
external male genitalia. This report describes the molecular analysis of the
5alpha-reductase type 2 gene in a Brazilian patient who was raised as a female,
underwent a reversal of gender role behavior, and is now a married man. This
patient is a compound heterozygote bearing an A-->G mutation within exon 2,
changing codon 126 from Glu to Arg on one allele and a novel single base
deletion (418delT) causing a frameshift mutation at codon 140 in the same exon,
on the other allele. This last mutation probably leads to the synthesis of a
truncated protein, because a premature termination signal is created at codon
159. The observation of ambiguous genitalia in the newborn signals a medical,
surgical and psychological emergency. The most crucial decision will be the
choice of sex assignment. Rapid and precise diagnosis is thus essential. In XY
newborns with normal/high plasma testosterone (T), partial androgen
insensitivity syndrome (PAIS) is usually the first diagnosis evoked, which
implies an androgen receptor (AR) defect. The diagnosis of
steroid-5-alpha-reductase deficiency is rarely considered by the paediatrician.
We report three new SRD5A2 gene mutations in four newborns from France, Morocco
and Turkey. The newborns presented with ambiguous genitalia and normal plasma T
values and the initial diagnosis\PAIS. In all four cases, normal sequences of
the complete AR gene excluded this diagnosis and raised the hypothesis of
5α-reductase deficiency. The entire coding region (5 exons) of the SRD5A2 gene
was assessed by PCR and direct sequencing analysis. For patient 1, we identified
a new homozygous 2bp deletion in exon 1 (c.122_123delAG). Patient 2 had a known
homozygous mutation, p.G115D, in exon 2. New compound heterozygous mutations in
exon 4 (p.A215V) and exon 5 (p.X255Q) were found in patient 3. Patient 4
presented a new substitution in exon 1 (p.S14R) associated with a known
polymorphism (p.V89L). Our data confirm our previous experience and clearly
demonstrate that a 5-α reductase defect should be considered in all XY newborns
with ambiguous genitalia and normal plasma T secretion, whatever their
geographic area or ethnic group; moreover, this defect was not linked to
specific phenotype. Early molecular diagnosis is indispensable for the crucial
decision of the newborn's sex of rearing. BACKGROUND: 5α steroid reductase deficiency (5αSRD) is an autosomal recessive
enzymatic deficiency and mutations in the 5α steroid reductase type 2 gene
(SRD5A2) result in male pseudohermaphrodism caused by decreased
dihydrotestosterone (DHT) synthesis.
AIM: To identify the specific mutations of the SRD5A2 gene in Cypriot patients
with 5αSRD.
SUBJECTS AND METHODS: Five unrelated patients with 46,XY karyotype were
examined. Four of them were born with ambiguous genitalia and 1 patient, who was
raised as girl, presented with primary amenorrhea. The hCG test was informative
(elevated testosterone/DHT) of 5αSRD in 3 out of 4 subjects. Sequencing of the
SRD5A2 gene was completed for all patients. Genomic DNA was also isolated from a
total of 204 healthy unrelated Cypriot subjects. Screening for the IVS1-2A>G
mutation was performed by using direct sequencing and restriction enzyme
analysis.
RESULTS: The IVS1-2A>G was identified in homozygosity in 3 patients and in a
compound heterozygote state in the other 2 patients, in combination with p.P181L
and p.R171S in exon 3, respectively. The carrier frequency in the Cypriot
population for the IVS1-2A>G mutation was estimated to be 0.98% or 2 in 204.
CONCLUSIONS: The same IVS1-2A>G mutation in the SRD5A2 gene seems to
characterize all Cypriot patients with 5αSRD diagnosed so far. Furthermore this
relatively rare genetic defect, which has only been reported previously in a
single case in the Eastern Mediterranean region, is very likely to be the result
of a founder effect. OBJECTIVE: To determine the genetic cause of primary amenorrhea.
DESIGN: Case series.
SETTING: Pediatric endocrinology, endocrinology, and gynecology departments of
academic hospitals.
PATIENT(S): Three adolescents and one young woman 46, XY patients with srd5A2
gene mutations.
MAIN OUTCOME MEASURE(S): Genetic analysis of srd5A2.
RESULT(S): We report four srd5A2 gene mutations in three adolescents and one
young woman with 46,XY primary amenorrhea. All presented clitoromegaly and two
presented hypospadias; all had been reared as females. Virilization of the
external genitalia was noted in the pubertal period in all four patients. Three
were maintained in the female sex of rearing by personal choice, and the fourth
switched gender. We identified the homozygous substitutions p.L55Q (exon 1),
p.Q56R (exon 1), and p.N193S (exon 4), in patients 1, 2, and 3, respectively.
Patient 4 had compound heterozygous mutations, a new c.34delG (exon 1)
associated with p.R246W (exon 5). All patients had high plasma T levels (ranges,
16.2-23.2 nmol/L; normal female teenage range, 0.35-2 nmol/L).
CONCLUSION(S): Our data clearly demonstrate that 5α-reductase deficiency should
be considered in XY adolescents with primary amenorrhea and no breast
development associated with virilization at puberty and high plasma T. Positive
parental consanguinity should reinforce the diagnostic orientation. CONTEXT: In 46,XY disorders of sex development, 5α-reductase deficiency is rare
and is not usually the first-intention diagnosis in newborn ambiguous genitalia,
contrary to partial androgen insensitivity syndrome. Yet the cause of ambiguous
genitalia may guide sex assignment, and rapid, precise diagnosis of 5α-reductase
deficiency is essential.
OBJECTIVE: The aim of the study was to describe relevant data for clinical
diagnosis, biological investigation, and molecular determination from 55
patients with srd5A2 mutations identified in our laboratory over 20 yr to
improve early diagnosis.
SETTING: The study was performed at Montpellier University Hospital.
PATIENTS: We studied a cohort of 55 patients with srd5A2 gene mutations.
MAIN OUTCOME MEASURE(S): Genetic analysis of srd5A2 was conducted.
RESULTS: Clitoromegaly (49.1%) and microphallus with various degrees of
hypospadias (32.7%) were frequent phenotypes. Female external genitalia (7.3%)
and isolated micropenis (3.6%) were rare. Seventy-two percent of patients were
initially assigned to female gender; five of them (12.5%) switched to male sex
in peripuberty. Over 72% of patients were considered for 5α-reductase deficiency
diagnosis when the testosterone/dihydrotestosterone cutoff was 10. In 55
patients (with 20 having a history of consanguinity), we identified 33 different
mutations. Five have never been reported: p.G32S, p.Y91H, p.G104E, p.F223S, and
c.461delT. Homozygous mutations were present in 69.1% of cases, compound
heterozygous mutations in 25.5%, and compound heterozygous mutations alone with
the V89L polymorphism in 5.4%. Exons 1 and 4 were most affected, with 35.8 and
21.7% mutant alleles per exon, respectively.
CONCLUSIONS: In the largest cohort to date, we demonstrate a wide spectrum of
phenotypes and biological profiles in patients with 5α-reductase deficiency,
whatever their geographical or ethnic origins. CONTEXT: Although a rare occurrence, previously undiagnosed disorders of sex
development (DSD) with hyperandrogenism are sometimes detected by hormonal
screening during the international sports competitions. Identifying the cause of
XY,DSD raises medical and ethical concerns, especially with regard to issues of
the eligibility to compete.
OBJECTIVE: The aim of this study was to determine whether the detection of high
plasma T in young elite female athletes during hormonal screening would reveal
an unsuspected XY DSD.
SETTING: The study was performed in the Nice and Montpellier University
Hospitals (France), which collaborate as reference centers for DSD in elite
athletes on behalf of sports governing bodies.
PATIENTS: Four cases of elite young athletes with female phenotypes but high
plasma T detected during hormonal screening were investigated for undiagnosed XY
DSD.
MAIN OUTCOME MEASURES: Evaluation of clinical, biological, radiological
(magnetic resoce imaging and dual-energy x-ray absorptiometry) and genetic
characteristics was conducted.
RESULTS: The 4 athletes presented as tall, slim, muscular women with a male bone
morphotype, no breast development, clitoromegaly, partial or complete labial
fusion, and inguinal/intralabial testes. All reported primary amenorrhea. The
hormonal analysis evidenced plasma T within the male range, the karyotype was
46, XY, and molecular analysis of the 5α-reductase type 2 (srd5A2) gene
identified a homozygotic mutation in 2 cases, a heterozygotic compound in 1
case, and a deletion in 1 case.
CONCLUSION: 5α-Reductase deficiency should be investigated in elite young female
athletes with primary amenorrhea and high male T levels detected during
antidoping programs to identify undiagnosed XY DSD. Steroid 5-alpha-reductase 2 deficiency is a rare disorder leading to male
pseudohermaphroditism, a condition characterized by incomplete differentiation
of male genitalia in 46,XY patients. Here, we report a case of a 21-year-old
woman from Ardabil who presented with primary amenorrhea, ambiguous genitalia,
and lack of breast development. All of the serum hormone profiles were normal
except for raised serum total testosterone. Testosterone to DHT ratio (T/DHT)
was elevated before (15.72) and further increased after hCG stimulation (32.46).
A chromosomal study revealed a 46,XY karyotype. A bilateral gonadectomy,
recessive cliteroplasty, urethroplasty, and vaginoplasty were performed and
hormonal replacement therapy using estrogen was started. In conclusion, the
diagnosis of 5-alpha-reductase 2 deficiency may be suspected in infants with
ambiguous genitalia or in adolescents or young adults with the characteristic
phenotype and serum hormone profiles. INTRODUCTION: Few studies exist on the psychosexual outcome of homogeneous
groups of individuals with 5α-reductase deficiency type 2 (5α-RD-2) and the
relation between gender changes and parental hostile and benevolent sexism,
which are two components of ambivalent sexism that assume a stereotypical
approach toward women in an overtly negative way or a chivalrous, seemingly
positive way.
AIM: To report on the psychosexual outcome of individuals with 5α-RD-2 and to
investigate its relation to the level of parental sexism in a relatively large
sample of Iranians with 5α-RD-2.
METHODS: Twenty participants (mean age = 19.5 years, SD = 6.345) with a
molecularly confirmed diagnosis of 5α-RD-2 who were assigned the female gender
at birth and raised as female were included in the study. Participants and their
parents were interviewed and their medical records were assessed. Parents also
completed the Ambivalent Sexism Inventory (ASI), which includes hostile and
benevolent sexism subscales.
MAIN OUTCOME MEASURES: Psychosexual outcome and parental hostile and benevolent
sexism measurements.
RESULTS: Twelve of 20 participants (60%) were diagnosed with gender identity
disorder not otherwise specified (Diagnostic and Statistical Manual of Mental
Disorders, Fourth Edition, Text Revision). Ten of these transitioned to the male
gender. The other 10 participants (50%), including the two diagnosed with gender
identity disorder not otherwise specified, continued living in a female gender
role. When comparing the ASI subscale scores between families of participants
who changed their gender and those who did not, no significant difference was
found for ASI total and hostile sexism scores, but there was a difference for
benevolent sexism (P = .049): those whose daughters had changed their gender had
higher benevolent sexism scores.
CONCLUSION: The high prevalence of gender change and gender dysphoria reported
in the literature was confirmed in this relatively large and homogeneous sample
of Iranians with 5-α-RD-2 raised as female. Prenatal exposure to testosterone is
hypothesized to play a role in the development of gender identity and
sexual orientation, but parental attitudes also might be important. Although
gender change in individuals with 5-α-RD-2 is often attributed to high levels of
hostile sexism in some cultures, our findings show this to be associated with
benevolent sexism. |
Has ubrogepant entered clinical phase III trials? | Yes, ubrogepant has entered phase III trials. | Ubrogepant (MK-1602) is a novel, oral, calcitonin gene-related peptide receptor
antagonist in clinical development with positive phase III outcomes for acute
treatment of migraine. This paper describes the population exposure-response
(E-R) modeling and simulations, which were used to inform the phase III
dose-selection rationale, based on ~ 800 participants pooled across two phase
IIb randomized dose-finding clinical trials. The E-R model describes the placebo
and ubrogepant treatment effects based on migraine pain end points (2-hour pain
relief and 2-hour pain freedom) at various dose levels. Sensitivity analyses
were conducted to evaluate various assumptions of placebo response in light of
the high placebo response observed in one phase II trial. A population
pharmacokinetic model describing the effect of formulations was included in the
E-R simulation framework to assess potential dose implications of a formulation
switch from phase II to phase III. Model-based simulations predict that a dose
of 25 mg or higher is likely to achieve significantly better efficacy than
placebo with desirable efficacy levels. The understanding of E-R helped support
the dose selection for the phase III clinical trials. INTRODUCTION: Migraine is a neurovascular disorder involving neurogenic
inflammation and transmission of trigeminovascular nociceptive pathways mediated
by Calcitonin Gene-Related Peptide (CGRP). Several small molecules antagonizing
the CGRP receptor have been developed as migraine-specific acute medications.
The CGRP receptor antagonist ubrogepant, also known as MK-1602, has been
recently evaluated in phase III clinical trials for clinical efficacy and
long-term safety as an abortive migraine treatment.
AREAS COVERED: This paper discusses the pharmacodynamics, pharmacokinetics,
clinical efficacy, safety, and tolerability profile of ubrogepant for the acute
treatment of migraine with or without aura.
EXPERT OPINION: Ubrogepant, a selective CGRP antagonist belonging to the gepants
family, has been evaluated in large short- and long-term Phases 2 and 3 clinical
trials aimed to assess clinical efficacy and safety as acute migraine
medication. It did not significantly affect liver function and was not
associated with other serious adverse events. Long-term non-serious adverse
events were similar between placebo and ubrogepant. The efficacy was evaluated
in large placebo-controlled studies and ubrogepant 50 mg and 100 mg was
superior, even if the therapeutic gain seems to be low. Nevertheless, the
favorable safety profile compared to other abortive drugs makes ubrogepant a
promising option for the acute treatment of migraine. Migraine is the primary headache disorder affecting a significant population
worldwide. Ubrogepant is an orally bioavailable calcitonin gene-related peptide
(CGRP) receptor antagonist (gepant) approved by the U.S. Food and Drug
Administration (FDA) for the acute treatment of migraine headaches with or
without aura in adults. Ubrogepant is the first oral CGRP receptor antagonist
approved for the acute treatment of migraine. CGRP is an important key mediator
of migraine pain; CGRP levels have been shown to be significantly higher during
a migraine attack. Two pivotal phase III clinical trials (ACHIEVE I and ACHIEVE
II) demonstrated effectiveness and safety of ubrogepant in acute migraine
attacks. Ubrogepant can be administered as 50- and 100-mg tablets, with a
maximum dose of 200 mg within 48 h. Besides minimizing pain, the drug is equally
effective in alleviating migraine-associated symptoms such as nausea,
photophobia and sound sensitivity. Unlike other gepants, ubrogepant is free from
hepatotoxicity at the therapeutic doses. In certain cases (1 in 5), a full
relief of pain was achieved with a single dose of the drug. The molecule is not
effective as a preventive migraine therapy. The present review discusses the
background, preclinical and clinical pharmacology, indication and safety of
ubrogepant for the treatment of migraine attacks. |
How many nucleotides long is the HOTAIR CNE? | The HOTAIR CNE is a 32-nucleotide long conserved noncoding element | Author information:
(1)Biotech Research and Innovation Centre, Department of Health and Medical
Sciences, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N,
Denmark. Electronic address: [email protected].
(2)Biotech Research and Innovation Centre, Department of Health and Medical
Sciences, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N,
Denmark.
(3)Institute of Cancer and Genomics Sciences, College of Medical and Dental
Sciences, University of Birmingham, Edgbaston, B15 2TT Birmingham, UK.
(4)Broegelmann Research Laboratory, Department of Clinical Science, University
of Bergen, Bergen, Norway; Department of Microbiology, Faculty of Biochemistry,
Biophysics and Biotechnology, and Malopolska Centre of Biotechnology,
Jagiellonian University, Karkow, Poland.
(5)Institute of Clinical Sciences MRC Clinical Sciences Centre, Faculty of
Medicine, Imperial College London, Hammersmith Hospital Campus, Du Cane Road,
London W12 0NN, UK; Sars International Centre for Marine Molecular Biology,
University of Bergen, 5008, Bergen, Norway.
(6)Institute of Cancer and Genomics Sciences, College of Medical and Dental
Sciences, University of Birmingham, Edgbaston, B15 2TT Birmingham, UK.
Electronic address: [email protected].
(7)Biotech Research and Innovation Centre, Department of Health and Medical
Sciences, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N,
Denmark. Electronic address: [email protected]. |
What symptoms are included in the narcolepsy pentad? | Narcolepsy is a chronic sleep disorder characterized by a pentad of excessive daytime sleepiness (EDS), cataplexy, sleep paralysis, hypnagogic/hypnopompic hallucinations, and disturbed nocturnal sleep. | Narcolepsy is a chronic sleep disorder characterized by a pentad of excessive
daytime sleepiness (EDS), cataplexy, sleep paralysis, hypnagogic/hypnopompic
hallucinations, and disturbed nocturnal sleep. While non-pharmacological
treatments are sometimes helpful, more than 90% of narcoleptic patients require
a pharmacological treatment. Areas covered: The present review is based on an
extensive Internet and PubMed search from 1994 to 2017. It is focused on drugs
currently in development for the treatment of narcolepsy. Expert opinion:
Currently there is no cure for narcolepsy, with treatment focusing on symptoms
control. However, these symptomatic treatments are often unsatisfactory. The
research is leading to a better understanding of narcolepsy and its symptoms.
New classes of compounds with possible applications in the development of novel
stimulant/anticataplectic medications are described. H3 receptor antagonists
represent a new therapeutic option for EDS in narcolepsy. JZP-110, with its
distinct mechanism of action, would be a new therapeutic option for the
treatment of EDS in the coming years. In the future, hypocretin-based therapies
and immune-based therapies, could modify the clinical course of the disease.
However, more information would be necessary to completely understand the
autoimmune process and also how this process can be altered for therapeutic
benefits. BACKGROUND: Narcolepsy is a disabling sleep-wake disorder characterized by the
pentad symptoms of excessive daytime sleepiness, sleep paralysis, sleep
fragmentation, sleep-related hallucinations, and cataplexy. There is no curative
therapy for narcolepsy. Treatment is therefore symptom directed. Symptom
management is generally directed at improving excessive daytime sleepiness,
sleep fragmentation, and cataplexy. First-line treatment for excessive daytime
sleepiness is typically daily use of wake-promoting agents, such as modafinil or
armodafinil, or stimulant therapy, such as methylphenidate or amphetamines.
Alternatively, sodium oxybate can be used nightly for improved cataplexy, sleep
consolidation, and following day wakefulness. These therapies can be limited in
some patients because of inadequate efficacy, poor tolerability, or side
effects.
METHODS: We describe five narcolepsy patients with severe excessive daytime
sleepiness who had an inadequate response or experienced side effects with the
initial therapies but had a positive response to treatment with baclofen.
RESULTS: These patients reported subjective improvement in sleep maintece
without fragmentation and daytime sleepiness. Average Epworth Sleepiness Scale
assessment before treatment was 15.8 with post-treatment assessment being 10.4
(P < 0.05).
CONCLUSIONS: Baclofen may be an effective treatment for excessive daytime
sleepiness and sleep fragmentation in narcolepsy and warrants further study. Disrupted nighttime sleep is one of the pentad of symptoms defining Narcolepsy.
REM sleep behavior disorder (RBD) largely contributes to night sleep disruption
and narcolepsy is the most common cause of secondary RBD. However, RBD linked to
narcolepsy (N-RBD) has been insufficiently characterized, leaving unsolved a
number of issues. Indeed, it is still debated whether N-RBD is an intrinsic
feature of narcolepsy, as indubitable for cataplexy, and therefore strictly
linked to the cerebrospinal fluid hypocretin-1 (CSF hcrt-1) deficiency, or an
associated feature, with a still unclear pathophysiology. The current review
aims at rendering a comprehensive state-of-the-art of N-RBD, highlighting the
open and unsettled topics. RBD reportedly affects 30-60% of patients with
Narcolepsy type 1 (NT1), but it may be seen also in Narcolepsy type 2 (NT2).
When compared to idiopathic/isolated RBD (iRBD), N-RBD has been reported to be
characterized by less energetic and quieter episode, which however occur with
the same probability in the first and the second part of the night and sometime
even subcontinuously. N-RBD patients are generally younger than those with iRBD.
N-RBD has been putatively linked to wake-sleep instability due to CSF hcrt-1
deficiency, but this latter by itself cannot explain completely the phenomenon
as N-RBD has not been universally linked to low CSF hcrt-1 levels and it may be
observed also in NT2. Therefore, other factors may probably play a role and
further studies are needed to clarify this issue. In addition, therapeutic
options have been poorly investigated. INTRODUCTION: Narcolepsy is a chronic sleep disorder characterized by a pentad
of excessive daytime sleepiness (EDS), cataplexy, sleep paralysis,
hypnagogic/hypnopompic hallucinations, and disturbed nocturnal sleep. Treatment
of narcolepsy remains challenging and current therapy is strictly
symptomatically based.
AREAS COVERED: The present manuscript is based on an extensive Internet and
PubMed search from 1990 to 2020. It is focused on the clinical and
pharmacological properties of pitolisant in the treatment of narcolepsy.
EXPERT OPINION: Currently there is no cure for narcolepsy. Although efforts have
been made, current treatments do not always allow to obtain an optimal control
of symptoms. Pitolisant is an antagonist/inverse agonist of the histamine H3
autoreceptor. Its mechanism of action is novel and distinctive compared to the
other available therapies for narcolepsy. Clinical trials suggest that
pitolisant administered at a dose of ≤36 mg/day is an effective treatment option
for narcolepsy, reducing EDS and cataplexy. Pitolisant is available as oral
tablets and offers a convenient once-daily regimen. Pitolisant is generally well
tolerated and showed minimal abuse potential in animals and humans. Long-term
studies comparing the effectiveness and tolerability of pitolisant with active
drugs (e.g. modafinil, sodium oxybate) are needed. |
What is the function of osteolectin? | C-type lectin domain family 11 member A (Clec11a), also known as stem cell growth factor (SCGF), C-type lectin superfamily member 3 (CLECSF3), or osteolectin was initially identified as a growth factor for hematopoietic progenitor cells. | C-type lectin domain family 11 member A (Clec11a), also known as stem cell
growth factor (SCGF), C-type lectin superfamily member 3 (CLECSF3), or
osteolectin was initially identified as a growth factor for hematopoietic
progenitor cells. The human Clec11a gene encodes a polypeptide of 323 amino
acids with characteristics of a secreted glycoprotein encompassing two
integrin-binding motifs, RGD (Arg-Gly-Asp) and LDT (Leu-Asp-Thr), a putative
leucine zipper domain, and a functional C-type lectin domain. It regulates
hematopoietic differentiation and homeostasis and exhibits a protective effect
against severe malarial anemia and lipotoxicity. Furthermore, Clec11a promotes
the differentiation of mesenchymal progenitors into mature osteoblasts in vitro
and plays an important role in the maintece of adult skeleton age-related
bone loss and fracture repair. Receptor ligand binding results in activation of
downstream signaling cascades including glycogen synthase kinase 3 (GSK3),
β-catenin, and Wnt, resulting in the expression of osteoblast-related gene
transcripts including Alp, Runx2, Lef1, and Axin2. In addition, Clec11a is also
associated with the development of several cancers, including leukemia, multiple
myeloma, and gastrointestinal tract tumors. To date, however, the mechanisms
governing transcription regulation of the Clec11a gene are not known and
remain to be uncovered. Understanding the function and mechanism of action of
Clec11a will pave the way for the development of Clec11a as a novel therapeutic
target for conditions such as cancer, anemia, and skeletal diseases. Author information:
(1)Institute for Regenerative Medicine, Shanghai East Hospital, Frontier Science
Center for Stem Cell Research, Shanghai Key Laboratory of Signaling and Disease
Research, School of Life Sciences and Technology, Tongji University, Shanghai
200092, China.
(2)Institute for Regenerative Medicine, Shanghai East Hospital, Frontier Science
Center for Stem Cell Research, Shanghai Key Laboratory of Signaling and Disease
Research, School of Life Sciences and Technology, Tongji University, Shanghai
200092, China; Department of Cardiology, Shanghai Tenth People's Hospital,
Tongji University School of Medicine, 1239 Siping Road, Shanghai 200072, China.
(3)Department of Pediatrics and Children's Research Institute, University of
Texas Southwestern Medical Center, Dallas, TX 75390, USA.
(4)Department of Implantology, School and Hospital of Stomatology, Tongji
University, Shanghai Engineering Research Center of Tooth Restoration and
Regeneration, Shanghai 200072, China.
(5)Institute of Orthopedic Surgery, Xijing Hospital, Fourth Military Medical
University, Xi'an 710032, China.
(6)Department of Orthopedics, Shanghai Key Laboratory of Orthopedic Implant,
Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of
Medicine, Shanghai 200011, China.
(7)Howard Hughes Medical Institute, University of Texas Southwestern Medical
Center, Dallas, TX 75390, USA; Department of Pediatrics and Children's Research
Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390,
USA.
(8)Institute for Regenerative Medicine, Shanghai East Hospital, Frontier Science
Center for Stem Cell Research, Shanghai Key Laboratory of Signaling and Disease
Research, School of Life Sciences and Technology, Tongji University, Shanghai
200092, China. Electronic address: [email protected]. |
What is ECMO? | Extracorporeal membrane oxygenation (ECMO) is an increasingly prevalent treatment for acute respiratory failure (ARF) | BACKGROUND: Extracorporeal membrane oxygenation (ECMO) is a form of long-term
cardiopulmonary bypass used to treat infants, children, and adults with
respiratory and/or cardiac failure despite maximal medical therapy. Mechanical
emergencies on extracorporeal membrane oxygenation (ECMO) have an associated
mortality of 25%. Thus, acquiring and maintaining the technical, behavioral, and
critical thinking skills necessary to manage ECMO emergencies is essential to
patient survival. Traditional training in ECMO management is primarily didactic
in nature and usually complemented with varying degrees of hands-on training
using a water-filled ECMO circuit. These traditional training methods do not
provide an opportunity for trainees to recognize and interpret real-time
clinical cues generated by human patients and their monitoring equipment. Adult
learners are most likely to acquire such skills in an active learning
environment. To provide authentic, intensive, interactive ECMO training without
risk to real patients, we used methodologies pioneered by the aerospace industry
and our experience developing a simulation-based training program in neonatal
resuscitation to develop a similar simulation-based training program in ECMO
crisis management, ECMO Sim.
METHODS: A survey was conducted at the 19th Annual Children's National Medical
Center ECMO Symposium to determine current methods for ECMO training. Using
commercially available technology, we linked a neonatal manikin with a standard
neonatal ECMO circuit primed with artificial blood. Both the manikin and circuit
were placed in a simulated neonatal intensive care unit environment equipped
with remotely controlled monitors, real medical equipment and human colleagues.
Twenty-five healthcare professionals, all of whom care for patients on ECMO and
who underwent traditional ECMO training in the prior year, participated in a
series of simulated ECMO emergencies. At the conclusion of the program, subjects
completed a questionnaire qualitatively comparing ECMO Sim with their previous
traditional ECMO training experience. The amount of time spent engaged in active
and passive activities during both ECMO Sim and traditional ECMO training was
quantified by review of videotape of each program.
RESULTS: Hospitals currently use lectures, multiple-choice exams, water drills,
and animal laboratory testing for their ECMO training. Modification of the
circuit allowed for physiologically appropriate circuit pressures (both pre- and
postoxygenator) to be achieved while circulating artificial blood continuously
through the circuit and manikin. Realistic changes in vital signs on the bedside
monitor and fluctuations in the mixed venous oxygen saturation monitor were also
effectively achieved remotely. All subjects rated the realism of the scenarios
as good or excellent and described ECMO Sim as more effective than traditional
ECMO training. They reported that ECMO Sim engaged their intellect to a greater
degree and better developed their technical, behavioral, and critical thinking
skills. Active learning (eg, hands-on activities) comprised 78% of the total
ECMO Sim program compared with 14% for traditional ECMO training (P < 0.001).
Instructor-led lectures predominated in traditional ECMO training.
CONCLUSION: Traditional ECMO training programs have yet to incorporate
simulation-based methodology. Using current technology it is possible to
realistically simulate in real-time the clinical cues (visual, auditory, and
tactile) generated by a patient on ECMO. ECMO Sim as a training program provides
more opportunities for active learning than traditional training programs in
ECMO management and is overwhelmingly preferred by the experienced healthcare
professionals serving as subjects in this study. Subjects also indicated that
they felt that the acquisition of key cognitive, technical, and behavioral
skills and transfer of those skills to the real medical domain was better
achieved during simulation-based training. Extracorporeal membrane oxygenation (ECMO) is used to support patients with
cardiopulmonary failure in the intensive care unit. The purpose of this study is
to determine what professional qualifications, equipment, and tests are used by
established ECMO programs registered with the Extracorporeal Life Support
Organization (ELSO). A survey link (Survey-Monkey) was e-mailed to the 110
registered ELSO program coordinators. Forty-nine responses were received. A test
of binomial portions showed that nurses were more likely to be ECMO providers
than respiratory therapists or perfusionists (p < .05). A chi2 test identified a
difference in the type of pump (roller or centrifugal) based on patient age (p <
.005). The most common monitoring/safety devices were battery back-up (84%),
pre- and post-oxygenator pressure (82%), mixed venous oxygen saturation
(80%),venous line pressure (76%), blood flowmeter (63%),bubble detector (61%),
point-of-care blood gases (59%), and in-line blood gas monitoring (47%).
Laboratory tests available included d-dimer (65%), plasma-free hemoglobin (63%),
anti-Xa plasma heparin concentration (43%), thromboelastograph (37%), and
heparin concentration using protamine titration (35%). This survey of
ELSO-registered centers represents an overview of current ECMO practices. INTRODUCTION: H1N1 influenza can cause severe acute lung injury (ALI).
Extracorporeal membrane oxygenation (ECMO) can support gas exchange in patients
failing conventional mechanical ventilation, but its role is still
controversial. We conducted a systematic review and meta-analysis on ECMO for
H1N1-associated ALI.
METHODS: CENTRAL, Google Scholar, MEDLINE/PubMed and Scopus (updated 2 January
2012) were systematically searched. Studies reporting on 10 or more patients
with H1N1 infection treated with ECMO were included. Baseline, procedural,
outcome and validity data were systematically appraised and pooled, when
appropriate, with random-effect methods.
RESULTS: From 1,196 initial citations, 8 studies were selected, including 1,357
patients with confirmed/suspected H1N1 infection requiring intensive care unit
admission, 266 (20%) of whom were treated with ECMO. Patients had a median
Sequential Organ Failure Assessment (SOFA) score of 9, and had received
mechanical ventilation before ECMO implementation for a median of two days. ECMO
was implanted before inter-hospital patient transfer in 72% of cases and in most
patients (94%) the veno-venous configuration was used. ECMO was maintained for a
median of 10 days. Outcomes were highly variable among the included studies,
with in-hospital or short-term mortality ranging between 8% and 65%, mainly
depending on baseline patient features. Random-effect pooled estimates suggested
an overall in-hospital mortality of 28% (95% confidence interval 18% to 37%; I²
= 64%).
CONCLUSIONS: ECMO is feasible and effective in patients with ALI due to H1N1
infection. Despite this, prolonged support (more than one week) is required in
most cases, and subjects with severe comorbidities or multiorgan failure remain
at high risk of in-hospital death. INTRODUCTION: Mortality of patients on extracorporeal membrane oxygenation
(ECMO) remains high. The objectives of this study were to assess the factors
associated with outcome of patients undergoing ECMO in a large ECMO referral
centre and to compare veno-arterial ECMO (VA ECMO) with veno-venous ECMO (VV
ECMO).
METHODS: We reviewed a prospectively obtained ECMO database and patients'
medical records between January 2005 and June 2011. Demographic characteristics,
illness severity at admission, ECMO indication, organ failure scores before ECMO
and the ECMO mode and configuration were recorded. Bleeding, neurological,
vascular and infectious complications that occurred on ECMO were also collected.
Demographic, illness, ECMO support descriptors and complications associated with
hospital mortality were analysed.
RESULTS: ECMO was initiated 158 times in 151 patients. VA ECMO (66.5%) was twice
as common as VV ECMO (33.5%) with a median duration significantly shorter than
for VV ECMO (7 days (first and third quartiles: 5; 10 days) versus 10 days
(first and third quartiles: 6; 16 days)). The most frequent complications during
ECMO support were bleeding and bloodstream infections regardless of ECMO type.
More than 70% of the ECMO episodes were successfully weaned in each ECMO group.
The overall mortality was 37.3% (37.1% for the patients who underwent VA ECMO,
and 37.7% for the patients who underwent VV ECMO). Haemorrhagic events, assessed
by the total of red blood cell units received during ECMO, were associated with
hospital mortality for both ECMO types.
CONCLUSIONS: Among neurologic, vascular, infectious and bleeding events that
occurred on ECMO, bleeding was the most frequent and had a significant impact on
mortality. Further studies are needed to better investigate bleeding and
coagulopathy in these patients. Interventions that reduce these complications
may improve outcome. Extracorporeal membrane oxygenation (ECMO) is a method of life support to
maintain cardiopulmonary function. Its use as a medical application has
increased since its inception to treat multiple conditions including acute
respiratory distress syndrome, myocardial ischemia, cardiomyopathy, and septic
shock. While complications including neurological and renal injury occur in
patients on ECMO, bleeding and coagulopathy are most common. ECMO is associated
with an inflammatory response promoting a hypercoagulable state, requiring
anticoagulation to avoid thromboembolism originating in the nonendothelial
surfaced circuit. However, excessive anticoagulation may result in bleeding
complications including intracerebral hemorrhage. Monitoring anticoagulation for
ECMO has its origins in cardiopulmonary bypass for cardiac surgery; however,
there is no ideal level of anticoagulation, no standardized method to monitor
anticoagulation, nor are all centers standardized on what is used for
anticoagulation. Multiple blood products are used in an effort to decrease
bleeding in the setting of anticoagulation, often in the setting of recent
surgery, and this leads to significant increases in cost for patients on ECMO
and transfusion-related complications. In this review article, we discuss the
evolution of the various modalities of ECMO, indications, contraindications, and
complications. Furthermore, we review the different strategies for
anticoagulation and treatment of coagulopathy while on ECMO. Finally, we discuss
the cost of ECMO and associated blood product transfusion. AIMS: To present a rare case of a post-partum spontaneous coronary artery
dissection (SCAD), a rarely seen condition which does not yet have a universally
agreed treatment method and the role of the intensive care unit (ICU) nurse when
caring for the adult ECMO patient.
BACKGROUND: The use of extra-corporeal membrane oxygenation (ECMO) for the adult
patient has increased slowly since the first reported successful treatment in
1972 (Hill et al., 1972) and is seen increasingly as a successful therapy when
conventional medical treatment has failed. In this case, a young lady 2 weeks
post-partum presented with acute coronary syndrome secondary to a SCAD. ECMO was
used successfully as a bridge to myocardial recovery following coronary artery
bypass grafts and cardiogenic shock.
DESIGN AND METHOD: A case study underpinned by a review of existing literature
relating to spontaneous coronary artery dissection and extra-corporeal membrane
oxygenation.
RESULTS AND CONCLUSIONS: ECMO is still a relatively new and invasive technology
but continues to improve survival rates in critically ill patients where
conventional medical treatment has failed. This article highlights requirement
for further research into several aspects of care for the adult ECMO patient.
Questions to be answered raised in this case study include recommendations for
the weaning of inotropes and vasoconstrictors, frequency of blood gas sampling
and whether it remains essential to have two nurses caring for the ECMO patient.
RELEVANCE TO CLINICAL PRACTICE: As medical treatment progresses, there is an
increasing demand for therapies such as ECMO to become more readily available
for the care of the critically ill adult patient. This article highlights
challenges that may be faced and what changes could be made to further improve
standards of care and survival rates for ECMO patients. Extracorporeal membrane oxygen (ECMO) has been used for many years in patients
with life-threatening hypoxaemia and/or hypercarbia. While early trials
demonstrated that it was associated with poor outcomes and extensive
haemorrhage, the technique has evolved. It now encompasses new technologies and
understanding that the lung protective mechanical ventilation it can facilitate
is inextricably linked to improving outcomes for patients. The positive results
from the CESAR (Conventional ventilation or ECMO for Severe Adult Respiratory
failure) study and excellent outcomes in patients who suffered severe influenza
A (H1N1/09) infection have established ECMO in the care of patients with severe
acute respiratory distress syndrome. Controversy remains as to at what point in
the clinical pathway ECMO should be employed; as a rescue therapy or more
pro-actively to enable and ensure high-quality lung protective mechanical
ventilation. The primary aims of this article are to discuss: 1) the types of
extracorporeal support available; 2) the rationale for its use; 3) the
relationship with lung protective ventilation; and 4) the current evidence for
its use. BACKGROUND: Extracorporeal membrane oxygenation (ECMO) is a form of life support
that targets the heart and lungs. Extracorporeal membrane oxygenation for severe
respiratory failure accesses and returns blood from the venous system and
provides non-pulmonary gas exchange. Extracorporeal membrane oxygenation for
severe cardiac failure or for refractory cardiac arrest (extracorporeal
cardiopulmonary resuscitation (ECPR)) provides gas exchange and systemic
circulation. The configuration of ECMO is variable, and several pump-driven and
pump-free systems are in use. Use of ECMO is associated with several risks.
Patient-related adverse events include haemorrhage or extremity ischaemia;
circuit-related adverse effects may include pump failure, oxygenator failure and
thrombus formation. Use of ECMO in newborns and infants is well established, yet
its clinical effectiveness in adults remains uncertain.
OBJECTIVES: The primary objective of this systematic review was to determine
whether use of veno-venous (VV) or venous-arterial (VA) ECMO in adults is more
effective in improving survival compared with conventional respiratory and
cardiac support.
SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials
(CENTRAL), MEDLINE (Ovid) and EMBASE (Ovid) on 18 August 2014. We searched
conference proceedings, meeting abstracts, reference lists of retrieved articles
and databases of ongoing trials and contacted experts in the field. We imposed
no restrictions on language or location of publications.
SELECTION CRITERIA: We included randomized controlled trials (RCTs), quasi-RCTs
and cluster-RCTs that compared adult ECMO versus conventional support.
DATA COLLECTION AND ANALYSIS: Two review authors independently screened the
titles and abstracts of all retrieved citations against the inclusion criteria.
We independently reviewed full-text copies of studies that met the inclusion
criteria. We entered all data extracted from the included studies into Review
Manager. Two review authors independently performed risk of bias assessment. All
included studies were appraised with respect to random sequence generation,
concealment of allocation, blinding of outcome assessment, incomplete outcome
data, selective reporting and other bias.
MAIN RESULTS: We included four RCTs that randomly assigned 389 participants with
acute respiratory failure. Risk of bias was low in three RCTs and high in one
RCT. We found no statistically significant differences in all-cause mortality at
six months (two RCTs) or before six months (during 30 days of randomization in
one trial and during hospital stay in another RCT). The quality of the evidence
was low to moderate, and further research is very likely to impact our
confidence in the estimate of effects because significant changes have been
noted in ECMO applications and treatment modalities over study periods to the
present.Two RCTs supplied data on disability. In one RCT survival was low in
both groups but none of the survivors had limitations in their daily activities
six months after discharge. The other RCT reported improved survival without
severe disability in the intervention group (transfer to an ECMO centre ± ECMO)
six months after study randomization but no statistically significant
differences in health-related quality of life.In three RCTs, participants in the
ECMO group received greater numbers of blood transfusions. One RCT recorded
significantly more non-brain haemorrhage in the ECMO group. Another RCT reported
two serious adverse events in the ECMO group, and another reported three adverse
events in the ECMO group.Clinical heterogeneity between studies prevented
meta-analyses across outcomes. We found no completed RCT that had investigated
ECMO in the context of cardiac failure or arrest. We found one ongoing RCT that
examined patients with acute respiratory failure and two ongoing RCTs that
included patients with acute cardiac failure (arrest).
AUTHORS' CONCLUSIONS: Extracorporeal membrane oxygenation remains a rescue
therapy. Since the year 2000, patient treatment and practice with ECMO have
considerably changed as the result of research findings and technological
advancements over time. Over the past four decades, only four RCTs have been
published that compared the intervention versus conventional treatment at the
time of the study. Clinical heterogeneity across these published studies
prevented pooling of data for a meta-analysis.We recommend combining results of
ongoing RCTs with results of trials conducted after the year 2000 if no
significant shifts in technology or treatment occur. Until these new results
become available, data on use of ECMO in patients with acute respiratory failure
remain inconclusive. For patients with acute cardiac failure or arrest, outcomes
of ongoing RCTs will assist clinicians in determining what role ECMO and ECPR
can play in patient care. Extracorporeal membrane oxygenation (ECMO) is the short-term (days to weeks)
support of patients with severe respiratory and/or cardiac failure. The use of
these devices has been well established in paediatric and post-heart and lung
transplantation patients; however, its use in patients with severe acute
respiratory distress syndrome (ARDS) has gained acceptance as standard clinical
practice over the past decade. The results of the CESAR trial (Conventional
ventilation or ECMO for Severe Adult Respiratory failure) showed significant
survival benefit for patients with ARDS undergoing ECMO. Substantial numbers of
radiological examinations are performed in this patient group, prompting the
need for general radiologists to understand the radiological appearances of
these devices and associated complications. In this review, we highlight the
uses, subtypes, physiology, normal appearances, and complications of ECMO. An
example of the chronological radiographic images in the perioperative period
demonstrates the importance of discriminating normal appearances associated with
EMCO. Extracorporeal Membrane Oxygenation (ECMO) represents a useful tool to support
the lungs and the heart when all conventional therapies failed and the patients
are at risk of death. While the Extracorporeal Life Support Organization (ELSO)
collects data from different institutions that joined the Registry and reports
overall outcome, individual centres often collide with results below
expectations, either in adults and in paediatric population. Some authors
suggest that poor outcomes could be overcome with a programme dedicated to ECMO,
with specialized professionals adequately trained on ECMO and with a consistent
number of procedures. In 2012, The IRCCS PSD ECMO Programme was instituted with
the specific aim of achieving better results than hitherto obtained. After only
1 year of activity, the results justified the programme, with a better survival
rate for each group investigated, particularly in adults, but surprisingly in
paediatrics too, where the results were better than what reported by ELSO.
Although the number of patients treated with ECMO is still growing up, the
effects of the ECMO programme continue to exert a positive action on outcome
even now. The present article reports data on survival, blood loss, and blood
consumption during ECMO in the last few years at our institution. PURPOSE: Extracorporeal membrane oxygenation (ECMO) is an increasingly prevalent
treatment for acute respiratory failure (ARF). To evaluate the impact of ECMO
support on long-term outcomes for critically ill adults with ARF.
METHODS: We searched electronic databases 1948 through to November 30 2016;
selected controlled trials or observational studies of critically ill adults
with acute respiratory distress syndrome, examining long-term morbidity
specifically health-related quality of life (HRQL); 2 authors independently
selected studies, extracted data, and assessed methodological quality.
ANALYSIS: Of the 633 citations, 1 randomized controlled trial and 5
observational studies met the selection criteria. Overall quality of
observational studies was moderate to high (mean score on Newcastle-Ottawa
scale, 7.2/9; range, 6-8). In 3 studies (n = 245), greater decrements in HRQL
were seen for survivors of ECMO when compared to survivors of conventional
mechanical ventilation (CMV) as measured by the Short Form 36 (SF-36) scores
([ECMO-CMV]: 5.40 [95% confidence interval, CI, 4.11 to 6.68]). As compared to
CMV survivors, those who received ECMO experienced significantly less
psychological morbidity (2 studies; n = 217 [ECMO-CMV]: mean weighted difference
[MWD], -1.31 [95% CI, -1.98 to -0.64] for depression and MWD, -1.60 [95% CI,
-1.80 to -1.39] for anxiety).
CONCLUSIONS: Further studies are required to confirm findings and determine
prognostic factors associated with more favorable outcomes in survivors of ECMO. PURPOSE: Extra Corporeal Membrane Oxygenation (ECMO) is used in cases of severe
respiratory and/or circulatory failure over periods of several days to several
weeks. Its circuitry requires a closely monitored anticoagulation therapy that
is empirically supported by activated clotting time (ACT)-a method often
associated with large inter- and intraindividual variability. We aimed to
compare the measurement of heparin activity with ACT and the direct measurement
of the heparin activity (anti-Xa) in a large ECMO population.
METHODS: All patients treated by venoarterial or venovenous ECMO in our
intensive care unit between January 2014 and December 2015 were prospectively
included. A concomitant measurement of the anti-Xa activity and ACT was
performed on the same sample collected twice a day (morning-evening) for
unfractionated heparin adaptation with an ACT target range of 180 to 220
seconds.
RESULTS: One hundred and nine patients (men 69.7%, median age 54 years) treated
with ECMO (70.6% venoarterial) were included. Spearman analysis found no
correlation between anti-Xa and ACT (ρ < 0.4) from day 1 and worsened over time.
Kappa analysis showed no agreement between the respective target ranges of ACT
and anti-Xa.
CONCLUSIONS: We demonstrate that concomitant measurement of ACT and anti-Xa
activity is irrelevant in ECMO patients. Since ACT is poorly correlated with
heparin dosage, anti-Xa activity appears to be a more suitable assay for
anticoagulation monitoring. PURPOSE: Optimal timing of congenital diaphragmatic hernia (CDH) repair in
patients requiring extracorporeal membrane oxygenation (ECMO) remains
controversial. The "late ECMO repair" is an approach where the patient, once
deemed stable for decannulation, is repaired while still on ECMO to enable
expeditious return to ECMO if surgery induces instability. The goal of this
study was to investigate the potential benefit of this approach by evaluating
the rate of return to ECMO after repair.
METHODS: The CDH Study Group database was used to analyze CDH patients requiring
ECMO support. The primary outcome was return to ECMO within 72 h of CDH repair
among those repaired following ECMO decannulation ("post-ECMO" patients).
Secondary outcomes were death within 72 h of repair and cumulative death and
return to ECMO rate.
RESULTS: A total of 668 patients were repaired post-ECMO decannulation. Six
patients (0.9%) in the post-ECMO group required return to ECMO within 72 h of
surgery and a total of 19 (2.8%) died or returned to ECMO within 72 h of
surgery.
CONCLUSION: The rate of return to ECMO and death following CDH repair is
extremely low and does not justify the risks inherent to "on-ECMO" repair.
Patients stable to come off ECMO should undergo repair after decannulation. Over the last decade, the use of extracorporeal membrane oxygenation (ECMO) has
increased significantly. In some centers, ECMO has been deployed to manage
perioperative emergencies and plays a role in facilitating high-risk thoracic,
airway, and trauma surgery, which may not be feasible without ECMO support.
General anesthesiologists who usually manage these cases may not be familiar
with the initiation and management of patients on ECMO. This review discusses
the use of ECMO in the operating room for thoracic, airway, and trauma surgery,
as well as obstetric and perioperative emergencies. |
Which diseases are associated with the Yaa gene? | The Y-linked autoimmune accelerating gene mutation (yaa), first discovered in the BXSB mouse strain, is known to accelerate spontaneous autoantibody production and subsequent development of lupus disease. It has also been shown to be associated with various autoimmune conditions such as lupus-like syndrome, collagen induced arthrits and glomerulonephritis. | The BXSB/MpJ (BXSB) murine strain (H-2b) spontaneously develops an autoimmune
syndrome with features of systemic lupus erythematosus (SLE) that affects males
much earlier than females. A mutant gene located on the BXSB Y chromosome,
designated Yaa (Y chromosome-linked autoimmune acceleration), is responsible for
the acceleration of the disease observed in male BXSB mice. Studies on H-2
congenic and I-E transgenic mice have clearly demonstrated that the MHC class II
genes play a crucial role in the development or protection of SLE. However, the
MHC effect can be completely masked by the presence of the Yaa gene in mice with
certain genetic backgrounds. It is intriguing that the Yaa gene effect is
selective on autoimmune responses, varying in different lupus-prone mice.
Studies on immune responses against foreign antigens have shown that the Yaa
gene potentiates immune responses only against antigens to which mice are
genetically (H-2-linked) low-responding, but not high-responding. Thus, the
selective immune enhancing activity of the Yaa gene may be related to
differences in the capacity of T helper cells specific for given antigens.
Moreover, studies on Yaa(+)-Yaa- bone marrow cell chimeric mice have suggested
that a specific cognate interaction of T helper cells with Yaa+ B cells is
responsible for a selective enhancing effect of immune responses to foreign
antigens as well as autoantigens. It is significant that unlike the lpr
mutation, whose abnormality is associated with the capacity of the Fas antigen
to mediate apoptosis, the Yaa gene by itself is unable to induce significant
autoimmune responses in mice without apparent SLE background. This suggests that
the molecular defect of the Yaa gene is likely to differ from that of the lpr
gene, and that the Yaa gene effect requires the abnormal autosomal genome
present in lupus-prone mice. Based on these findings, a possible molecular
nature of the Yaa gene abnormality will be discussed. To investigate the specific contribution of select MHC class II genes on the
development of murine lupus, H-2 congenic (NZB x BXSB)F1 hybrid mice bearing
either H-2b/b, H-2d/b, or H-2d/d haplotypes were generated. We compared the
clinical development (autoantibody production and glomerulonephritis) of
systemic lupus erythematosus (SLE) in these three F1 hybrids in the presence or
absence of the mutant gene, Yaa (Y chromosome-linked autoimmune acceleration),
which normally accelerates the progression of murine SLE. (NZB x BXSB)F1 hybrid
female mice bearing either the H-2b/b or H-2d/b haplotype developed a rapid
course of severe SLE, while the appearance of disease was markedly delayed in
H-2d/d hybrid females. However, in the presence of the Yaa gene, H-2d/d F1 males
developed SLE as severe as H-2b/b and H-2d/b F1 males. These data indicate that
(a) the conventional H-2b is a haplotype leading to susceptibility for murine
SLE, while H-2d is a relatively resistant haplotype; (b) the H-2b haplotype
exhibits a domit effect on autoimmune responses, similar to the classical
MHC-linked Ir gene effect; and (c) most strikingly, the Yaa gene totally
abrogates the MHC effect on murine lupus in (NZB x BXSB)F1 hybrid mice. The Y-linked autoimmune accelerating gene mutation (yaa), first discovered in
the BXSB mouse strain, is known to accelerate spontaneous autoantibody
production and subsequent development of lupus disease. We have investigated the
role of the yaa gene in the development of the type II collagen (CII)-induced
arthritis (CIA), which is used as a model for rheumatoid arthritis. In contrast
to the accelerating effects on development of lupus autoimmunity we can show
that the presence of BXSB Y chromosome carrying the yaa gene block development
of CIA in F1 crosses with three normally CIA-susceptible strains, DBA/1, C3H.Q
and B10.Q. Backcross experiments showed an additional modulatory effect from
other BXSB genes or possibly from DBA/1 X chromosome. To evaluate the effect
mediated by the yaa gene alone, the BXSB Y chromosome was bred into the DBA/1
gene background. The DBA/1 congenic DBA/1.yaa male mice were less susceptible to
arthritis development than their DBA/1 counterparts. (B10.QxDBA/1.yaa)F1
acquired resistance to arthritis development similar to that of DBA/1.yaa,
indicating a role for the yaa gene alone. The serum levels of autoantibodies to
CII were significantly suppressed in all strains carrying yaa. In DBA/1.yaa mice
a reduced number of T cells were found to produce interferon-gamma after in
vitro stimulation with CII. Thus, although autoreactive B cells are important in
both diseases they play different roles in murine lupus and in CIA. BXSB mice spontaneously develop a lupus-like syndrome that is accelerated by the
Yaa gene (Y-linked autoimmune accelerator). We studied the phenotype of disease
in (B10 x BXSB)F1 and (BXSB x (B10 x BXSB)F1) backcross mice and genotyped 224
backcross animals to allow a microsatellite-based genome-wide linkage analysis
to be conducted. In the backcross population, three intervals on chromosome 1
showed significant linkage to disease, suggesting that multiple loci contribute
to the production of autoimmune disease. D1Mit5 at 32.8 cM was linked to
development of nephritis (chi(2) = 15.68, p = 7.5 x 10(-5)), as was D1Mit12 at
63.1 cM (chi(2) = 20.17, p = 7.1 x 10(-6)). D1Mit403 at 100 cM was linked to
anti-dsDNA Ab production (chi(2) = 17.28, p = 3.2 x 10(-5)). Suggestive linkages
to antinuclear Abs and nephritis were identified on chromosome 3, to
splenomegaly on chromosome 4, and to anti-ssDNA Ab production on chromosome 10.
Chromosome 4 and the telomeric region of chromosome 1 have previously been
linked to disease in other mouse models of systemic lupus erythematosus;
however, the centromeric regions of chromosome 1 and chromosomes 3 and 10 are
unique to BXSB. This implies that, though some loci may be common to a number of
mouse models of lupus, different clusters of disease genes confer disease
susceptibility in different strains of mice. In a subset of systemic lupus erythematosus (SLE) patients, antiphospholipid
syndrome, characterized by occurrence of anti-cardiolipin (CL) antibodies,
thrombocytopenia, thrombosis and recurrent intrauterine fetal death occurs. Male
(NZW x BXSB)F1 mice, carrying the BXSB Yaa gene, serve as a model for
SLE-associated antiphospholipid syndrome. Using microsatellite markers in the
NZW x (NZW x BXSB)F1 backcross male progeny, we mapped BXSB alleles contributing
to the generation of anti-CL antibodies, platelet-binding antibodies,
thrombocytopenia and myocardial infarction. Generation of each disease character
was controlled by two major independently segregating domit alleles, i.e.
those on chromosomes (Chr.) 4 and 17 for anti-CL antibodies, Chr. 8 and 17 for
both anti-platelet antibodies and thrombocytopenia and, to our surprise, Chr. 7
and 14 for myocardial infarction, and that a combination of the two alleles
appeared to produce full expression of each character, as a complementary gene
action. The alleles on Chr. 17 linked to the above three characters were all
mapped in close proximity to the H-2 complex. Therefore, no single factor such
as anti-CL antibodies can explain the pathogenesis of SLE-associated
antiphospholipid syndrome. Rather, a combination of susceptibility alleles such
as described here, along with additional modifying loci, i.e. BXSB Yaa and some
from NZW, characterizes unique SLE features in male (NZW x BXSB) F1 mice. There
are potentially important candidate genes which may be linked to the syndrome. In the present study, we mapped the major quantitative trait loci (QTL)
differing between the NZW and C57BL/6 inbred strains of mice by making use of
(NZW x C57BL/6.Yaa)F1 mice, a model in which the lupus-like autoimmune syndrome
observed in male mice is associated with the presence of an as yet unidentified
Y chromosome-linked autoimmune acceleration gene, Yaa. Linkage analysis of 126
C57BL/6 x (NZW x C57BL/6.Yaa)F1 backcross males provided evidence for a major
QTL on chromosome 7 controlling both the severity of glomerulonephritis and the
production of IgG anti-DNA autoantibody and retroviral gp70-anti-gp70 immune
complexes. Two additional QTL of C57BL/6 origin on chromosome 17 had no apparent
individual effects, but showed strong epistatic interaction with chromosome 7
QTL for disease severity and anti-DNA autoantibody production. Our data also
identified on chromosome 13 a QTL of NZW origin with a major effect on the level
of gp70, and showing an additive effect with the chromosome 7 QTL on the level
of gp70 immune complexes. Our study thus provides a model to dissect the complex
genetic interactions that result in manifestations of murine lupus-like disease. Murine acquired immunodeficiency syndrome (MAIDS) is characterized by
lymphoproliferation, polyclonal B cell activation resulting in the production of
autoantibodies, and a progressive immunodeficiency. These are all hallmarks of
some autoimmune diseases. Yaa is a Y-chromosome-linked gene that accelerates
autoimmune diseases in some autoimmune-prone strains of mice. To further
elucidate a possible relationship with autoimmunity, the effect of the Yaa gene
on MAIDS was investigated. Analysis of phenotypic and functional disease
parameters revealed that Yaa does not accelerate MAIDS disease. This is probably
due to the generalized activation of most or all lymphoid cells in MAIDS, which
cannot be enhanced by the Yaa gene. This result is in accordance with the
selective enhancing effect of the Yaa gene on the immune response against self
and foreign antigens in a specific genetic background. It suggests that the
autoimmune response associated with MAIDS is a secondary phenomenon.
Interestingly, even in wild-type C57BL/6 mice, autoantibody production may
contribute overproportionally to the hypergammaglobulinemia associated with
MAIDS. The accelerated development of systemic lupus erythematosus (SLE) in BXSB male
mice is associated with the presence of an as yet unidentified mutant gene, Yaa
(Y-linked autoimmune acceleration). In view of a possible role of marginal zone
(MZ) B cells in murine SLE, we have explored whether the expression of the Yaa
mutation affects the differentiation of MZ and follicular B cells, thereby
implicating the acceleration of the disease. In this study, we show that both
BXSB and C57BL/6 Yaa mice, including two different substrains of BXSB Yaa males
that are protected from SLE, displayed an impaired development of MZ B cells
early in life. Studies in bone marrow chimeras revealed that the loss of MZ B
cells resulted from a defect intrinsic to B cells expressing the Yaa mutation.
The lack of selective expansion of MZ B cells in diseased BXSB Yaa males
strongly argues against a major role of MZ B cells in the generation of
pathogenic autoantibodies in the BXSB model of SLE. Furthermore, a comparative
analysis with mice deficient in CD22 or expressing an IgM
anti-trinitrophenyl/DNA transgene suggests that the hyperreactive phenotype of
Yaa B cells, as judged by a markedly increased spontaneous IgM secretion, is
likely to contribute to the enhanced maturation toward follicular B cells and
the block in the MZ B cell generation. By assessing the development of Y-linked autoimmune acceleration (Yaa)
gene-induced systemic lupus erythematosus in C57BL/6 (B6) x (New Zealand Black
(NZB) x B6.Yaa)F(1) backcross male mice, we mapped three major susceptibility
loci derived from the NZB strain. These three quantitative trait loci (QTL) on
NZB chromosomes 1, 7, and 13 differentially regulated three different autoimmune
traits: anti-nuclear autoantibody production, gp70-anti-gp70 immune complex
(gp70 IC) formation, and glomerulonephritis. Contributions to the disease traits
were further confirmed by generating and analyzing three different B6.Yaa
congenic mice, each carrying one individual NZB QTL. The chromosome 1 locus that
overlapped with the previously identified Nba2 (NZB autoimmunity 2) locus
regulated all three traits. A newly identified chromosome 7 locus, designated
Nba5, selectively promoted anti-gp70 autoantibody production, hence the
formation of gp70 IC and glomerulonephritis. B6.Yaa mice bearing the NZB
chromosome 13 locus displayed increased serum gp70 production, but not gp70 IC
formation and glomerulonephritis. This locus, called Sgp3 (serum gp70 production
3), selectively regulated the production of serum gp70, thereby contributing to
the formation of nephritogenic gp70 IC and glomerulonephritis, in combination
with Nba2 and Nba5 in NZB mice. Among these three loci, a major role of Nba2 was
demonstrated, because B6.Yaa Nba2 congenic male mice developed the most severe
disease. Finally, our analysis revealed the presence in B6 mice of an H2-linked
QTL, which regulated autoantibody production. This locus had no apparent
individual effect, but most likely modulated disease severity through
interaction with NZB-derived susceptibility loci. The y-linked autoimmune accelerating (yaa) locus is a potent autoimmune disease
allele. Transcription profiling of yaa-bearing B cells revealed the
overexpression of a cluster of X-linked genes that included Tlr7. FISH analysis
demonstrated the translocation of this segment onto the yaa chromosome. The
resulting overexpression of Tlr7 increased in vitro responses to Toll-like
receptor (TLR) 7 signaling in all yaa-bearing males. B6.yaa mice are not overtly
autoimmune, but the addition of Sle1, which contains the autoimmune-predisposing
Slam/Cd2 haplotype, causes the development of fatal lupus with numerous
immunological aberrations. B6.Sle1yaa CD4 T cells develop the molecular
signature for T(FH) cells and also show expression changes in numerous cytokines
and chemokines. Disease development and all component autoimmune phenotypes were
inhibited by Sles1, a potent suppressor locus. Sles1 had no effect on
yaa-enhanced TLR7 signaling in vitro, and these data place Sles1 downstream from
the lesion in innate immune responses mediated by TLR7, suggesting that Sles1
modulates the activation of adaptive immunity in response to innate immune
signaling. The Y-linked autoimmune accelerating (Yaa) locus drives the transition to fatal
lupus nephritis when combined with B6.Sle1 in our C57BL/6J (B6)-congenic model
of systemic autoimmunity. We and others recently demonstrated that the
translocation of a cluster of X-linked genes onto the Y chromosome is the
genetic lesion underlying Yaa (Subramanian, S. et al., Proc. Natl. Acad. Sci.
USA 2006. 103: 9970-9975; Pisitkun, P. et al., Science 2006. 312: 1669-1672). In
male mice carrying Yaa, the transcription of several genes within the
translocated segment is increased roughly twofold. Although the translocated X
chromosome segment in Yaa may contain as many as 16 genes, the major candidate
gene for causation of the Yaa-associated autoimmune phenotypes has been TLR7. To
confirm the role of TLR7 in Yaa-mediated autoimmune phenotypes, we introgressed
a targeted disruption of TLR7 (TLR7(-)) onto B6.Sle1Yaa to produce
B6.Sle1YaaTLR7(-) and examined evidence of disease at 6 and 9 months of age. Our
results demonstrate that the up-regulation of TLR7 in the B6.Sle1Yaa strain is
responsible for splenomegaly, glomerular nephritis and the majority of the
cellular abnormalities of B, T and myeloid cells. The up-regulation of TLR7 was
also responsible for driving the infiltration and activation of leukocytes in
the kidney, in which activated T cells were a primary component. However, the
resolution of TLR7 up-regulation did not eliminate the enhanced humoral
autoimmunity observed in B6.SleYaa, suggesting that additional elements in the
translocation may contribute to the disease phenotype. |
Which receptors does bimagrumab block? | Bimagrumab blocks the activin type II receptors. | RATIONALE: Bimagrumab is a fully human monoclonal antibody that blocks the
activin type II receptors, preventing the activity of myostatin and other
negative skeletal muscle regulators.
OBJECTIVES: To assess the effects of bimagrumab on skeletal muscle mass and
function in patients with chronic obstructive pulmonary disease (COPD) and
reduced skeletal muscle mass.
METHODS: Sixty-seven patients with COPD (mean FEV1, 1.05 L [41.6% predicted];
aged 40-80 yr; body mass index < 20 kg/m2 or appendicular skeletal muscle mass
index ≤ 7.25 [men] and ≤ 5.67 [women] kg/m2), received two doses of either
bimagrumab 30 mg/kg intravenously (n = 33) or placebo (n = 34) (Weeks 0 and 8)
over 24 weeks.
MEASUREMENTS AND MAIN RESULTS: We assessed changes in thigh muscle volume (cubic
centimeters) as the primary endpoint along with 6-minute-walk distance (meters),
safety, and tolerability. Fifty-five (82.1%) patients completed the study. Thigh
muscle volume increased by Week 4 and remained increased at Week 24 in
bimagrumab-treated patients, whereas no changes were observed with placebo (Week
4: +5.9% [SD, 3.4%] vs. 0.0% [3.3%], P < 0.001; Week 8: +7.0% [3.7%] vs. -0.7%
[2.8%], P < 0.001; Week 16: +7.8% [5.1%] vs. -0.9% [4.5%], P < 0.001; Week 24:
+5.0% [4.9%] vs. -1.3% [4.3%], P < 0.001). Over 24 weeks, 6-minute-walk distance
did not increase significantly in either group. Adverse events in the bimagrumab
group included muscle-related symptoms, diarrhea, and acne, most of which were
mild in severity.
CONCLUSIONS: Blocking the action of negative muscle regulators through the
activin type II receptors with bimagrumab treatment safely increased skeletal
muscle mass but did not improve functional capacity in patients with COPD and
low muscle mass. Clinical trial registered with www.clinicaltrials.gov
(NCT01669174). |
Are PDXK mutations linked to polyneuropathy? | Yes, PDXK mutations are linked to polyneuropathy. | Author information:
(1)Institute of Human Genetics, Center for Molecular Medicine Cologne (CMMC),
Institute of Genetics, and Center for Rare Diseases Cologne, University of
Cologne, Cologne, Germany.
(2)Molecular and Clinical Sciences Institute, St. George's University of London,
Cranmer Terrace, London SW17 0RE, UK; Department of Neuromuscular Diseases, UCL
Institute of Neurology, Queen Square, London, WC1N 3BG, UK.
(3)Department of Neuromuscular Diseases, UCL Institute of Neurology, Queen
Square, London, WC1N 3BG, UK; Department of Neurology and Neurosurgery,
Institute of Emergency Medicine, Toma Ciorbă 1, 2052 Chisinau, Republic of
Moldova.
(4)Genetics and Genomic Medicine, Great Ormond Street Institute of Child Health,
University College London, London WC1E 6BT, UK.
(5)Neurology Dept., Ghaem Hospital, Medical School, Mashhad University of
Medical Sciences, Mashhad, Iran.
(6)Department of Molecular Genetics, Next Generation Genetic Polyclinic, Mashhad
009851, Iran.
(7)Molecular and Clinical Sciences Institute, St. George's University of London,
Cranmer Terrace, London SW17 0RE, UK; Department of Molecular Genetics, Next
Generation Genetic Polyclinic, Mashhad 009851, Iran.
(8)Cologne Center for Genomics (CCG), University of Cologne, Cologne, Germany.
(9)Institute of Human Genetics, Center for Molecular Medicine Cologne (CMMC),
Institute of Genetics, and Center for Rare Diseases Cologne, University of
Cologne, Cologne, Germany. Electronic address: [email protected]. |
Is avelumab effective for urothelial carcinoma? | Yes. Avelumab is an anti-programmed death-ligand 1 monoclonal antibody that is approved for the treatment of urothelial carcinoma. | Purpose We assessed the safety and antitumor activity of avelumab, a fully human
anti-programmed death-ligand 1 (PD-L1) IgG1 antibody, in patients with
refractory metastatic urothelial carcinoma. Methods In this phase Ib,
multicenter, expansion cohort, patients with urothelial carcinoma progressing
after platinum-based chemotherapy and unselected for PD-L1 expression received
avelumab 10 mg/kg intravenously every 2 weeks. The primary objectives were
safety and tolerability. Secondary objectives included confirmed objective
response rate (Response Evaluation Criteria in Solid Tumors [RECIST] version
1.1), progression-free survival, overall survival (OS), and PD-L1-associated
clinical activity. PD-L1 positivity was defined as expression by
immunohistochemistry on ≥ 5% of tumor cells. Results Forty-four patients were
treated with avelumab and followed for a median of 16.5 months (interquartile
range, 15.8 to 16.7 months). The data cutoff was March 19, 2016. The most
frequent treatment-related adverse events of any grade were fatigue/asthenia
(31.8%), infusion-related reaction (20.5%), and nausea (11.4%). Grades 3 to 4
treatment-related adverse events occurred in three patients (6.8%) and included
asthenia, AST elevation, creatine phosphokinase elevation, and decreased
appetite. The confirmed objective response rate by independent central review
was 18.2% (95% CI, 8.2% to 32.7%; five complete responses and three partial
responses). The median duration of response was not reached (95% CI, 12.1 weeks
to not estimable), and responses were ongoing in six patients (75.0%), including
four of five complete responses. Seven of eight responding patients had
PD-L1-positive tumors. The median progression-free survival was 11.6 weeks (95%
CI, 6.1 to 17.4 weeks); the median OS was 13.7 months (95% CI, 8.5 months to not
estimable), with a 12-month OS rate of 54.3% (95% CI, 37.9% to 68.1%).
Conclusion Avelumab was well tolerated and associated with durable responses and
prolonged survival in patients with refractory metastatic UC. Publisher: Az immunterápia modern hatóanyagainak, mint az immunellenõrzési
pontokon ható PD-1- (nivolumab, pembrolizumab) és PD-L1- (atezolizumab,
avelumab, durvalumab) blokkolóknak a megjelenésével új lehetõségek nyíltak a
lokálisan elõrehaladott és áttétes uroteliális tumoros betegek kezelésében. A
napjainkig publikált eredmények alapján hatékony terápiás opciót jelentenek
platinakezelés utáni progresszió esetén másod- és többed-, valamint ciszplatinra
alkalmatlan betegeknél elsõ vonalban is. A betegek túlélésének és a tumorválasz
idõtartamának eredményei igen biztatóak, hatékonyabbnak látszanak az adott
stádiumokban eddig alkalmazott kemoterápiás szerek publikált adatainál.
Toxicitási profiljuk általánosságban ugyancsak kedvezõbbnek tûnik. Az
immunrendszeri eredetû mellékhatások elõfordulása ritka, azok felismerése és
menedzselése felkészültséget és multidiszciplináris gondolkodást igényel. A
folyamatban levõ vizsgálatok értékelik az új szerek más hatáspontú (pl.
CTLA-4-gátló ipilimumab, tremelimumab vagy kemoterápiás) készítményekkel történõ
kombinációs eredményeit, valamint prediktív biomarkerek azonosítását a
hatékonyság további fokozása céljából. Összefoglalónkban az immunterápiás
hatóanyagok eddig publikált adatait foglaltuk össze uroteliális daganatok
kezelésében, valamint rövid áttekintést adunk a folyamatban levõ klinikai
vizsgálatokról. BACKGROUND: Avelumab has recently been approved by the Food and Drug
Administration for the therapy of Merkel cell carcinoma and urothelial
carcinoma. M7824 is a novel first-in-class bifunctional fusion protein
comprising a monoclonal antibody against programmed death-ligand 1 (PD-L1,
avelumab), fused to the extracellular domain of human transforming growth factor
beta (TGFβ) receptor 2, which functions as a TGFβ "trap." Advanced urothelial
tumors have been shown to express TGFβ, which possesses immunosuppressive
properties that promote cancer progression and metastasis. The rationale for a
combined molecule is to block the PD-1/PD-L1 interaction between tumor cells and
immune cell infiltrate and simultaneously reduce or eliminate TGFβ from the
tumor microenvironment. In this study, we explored the effect of M7824 on
invasive urothelial carcinoma cell lines.
METHODS: Human urothelial (transitional cell) carcinoma cell lines HTB-4, HTB-1,
and HTB-5 were treated with M7824, M7824mut (M7824 that is mutated in the
anti-PD-L1 portion of the molecule and thus does not bind PD-L1), anti-PD-L1
(avelumab), or IgG1 isotype control monoclonal antibody, and were assessed for
gene expression, cell-surface phenotype, and sensitivity to lysis by TRAIL,
antigen-specific cytotoxic T lymphocytes and natural killer cells.
RESULTS: M7824 retains the ability to mediate antibody-dependent cellular
cytotoxicity of tumor cells, although in some cases to a lesser extent than
anti-PD-L1. However, compared to anti-PD-L1, M7824 increases (A) gene expression
of molecules involved in T-cell trafficking in the tumor (e.g., CXCL11), (B)
TRAIL-mediated tumor cell lysis, and (C) antigen-specific CD8+ T-cell-mediated
lysis of tumor cells.
CONCLUSIONS: These studies demonstrate the immunomodulatory properties of M7824
on both tumor cell phenotype and immune-mediated lysis. Compared to anti-PD-L1
or M7824mut, M7824 induces immunogenic modulation of urothelial carcinoma cell
lines, rendering them more susceptible to immune-mediated recognition and lysis.
These findings show the relevance of the dual blockade of PD-L1 and TGFβ in
urothelial carcinoma cell lines and thus support the rationale for future
clinical studies of M7824 in patients with urothelial cancer. Metastatic urothelial carcinoma (UC) remains an aggressive disease associated
with limited treatment options and a reduced survival. In spite of this, the
first-line treatment based on platinum-based combinations has remained virtually
unchanged for the last 20-30 years. Similarly, before the advent of the immune
checkpoint inhibitors, there were no FDA-approved drugs for second-line therapy.
In the last few years, impressive signs of anti-tumor activity have been
reported with several immunotherapy agents targeting the programmed cell death-1
(PD-1) pathway. Avelumab, a PD-1 ligand (PD-L1) inhibitor, is currently being
investigated for the treatment of UC. Areas covered: This article will review
the pharmacological characteristics of avelumab, the efficacy studies which led
to its approval, its safety profile, as well as its place within the management
of urothelial carcinoma with immunotherapy. For that matter, we undertook a
literature review of all the studies assessing the pharmacology of avelumab and
its efficacy within clinical trials. Expert commentary: Avelumab has shown
promising antitumor activity and a manageable safety profile in patients with
UC. Its dual mechanism of action, blocking the interaction between PD-L1 and
PD-1 and promoting antibody-dependent cell-mediated cytotoxicity could
potentially be of great interest since it could produce synergistic clinical
efficacy. INTRODUCTION: Treatment strategy for inoperable and metastatic urothelial
carcinoma (mUC) has been revolutionized by the introduction of programmed cell
death protein 1 (PD-1) and programmed cell death protein ligand (PD-L1)
antibodies. During the last 3 decades treatment options were limited to
chemotherapy, making further treatment of patients whose disease progressed
under ongoing therapy or who were ineligible to receive cytotoxic therapy in the
first place, nearly impossible.
EVIDENCE ACQUISITION: Five antibodies including pembrolizumab (PD-L1 antibody),
atezolizumab (PD-1 antibody), nivolumab (PD-1 antibody), avelumab and durvalumab
(PD-L1 antibodies) have been approved in the treatment of advanced urothelial
carcinoma in first- and second-line treatment setting. The objective of this
review was to examine and compare the different cohorts and to discuss the
quality of the respective studies in order to set up selection criteria for
clinical decision making.
EVIDENCE SYNTHESIS: So far pembrolizumab and atezolizumab have demonstrated
overall survival (OS) benefit in phase II studies and have shown superiority
over standard chemotherapy in phase III studies which has granted them approval
in first and second-line treatment setting. Improved OS and durable responses
were also seen in phase Ib/II non-randomized, single-arm trials conducted with
nivolumab, avelumab and durvalumab and granting accelerated approval for
second-line treatment. The huge advantage of immunotherapy and one of the
reasons for its overall recognition is its good tolerability profile especially
in comparison to chemotherapy.
CONCLUSIONS: Pembrolizumab has to be recommended in second-line therapy due to
reporting in a phase III trial and OS survival benefit compared to chemotherapy
control group. In cisplatin-eligible and treatment-naïve patients with visceral
or liver metastases data also slightly favors pembrolizumab rather than
atezolizumab. Although immunotherapies have been employed for many decades, immune checkpoint
inhibitors have only recently entered the oncologic landscape. Avelumab is a
fully human monoclonal antibody that blocks the interaction between PD-L1 on
tumor cells and PD-1 on T cells, thereby inhibiting immunosuppression in the
tumor microenvironment and reducing tumor growth. Most early clinical trials of
avelumab as monotherapy and in combination regimens were part of the
international JAVELIN clinical trial program, which included more than 7000
patients in more than 30 trials with at least 15 tumor types. Avelumab has been
approved by the U.S. FDA for the treatment of metastatic Merkel cell carcinoma
and metastatic urothelial carcinoma that has progressed during or following
treatment with a platinum-based regimen. Its acceptable safety profile and
ability to induce durable responses in otherwise deadly tumors provide the
rationale for its use in other tumor types and in combination with other
therapies. OBJECTIVE: To estimate the budget impact of introducing avelumab as a
second-line (2L) treatment option for patients with locally advanced or
metastatic urothelial cancer (mUC) from the perspective of a US third-party
payer (commercial and Medicare).
METHODS: A budget impact model (BIM) with a three-year time horizon was
developed for avelumab. Efficacy and safety data were sourced from published
literature and US package inserts. The analysis was conducted in collaboration
with a specialist oncologist who validated clinical assumptions. Costs were
based on the number of eligible patients, time-to-treatment failure, overall
survival, adverse events (AEs), and projected market shares of various
treatments.
RESULTS: In a hypothetical commercial health plan of 30,000,000 members, 884
patients were estimated to be eligible for 2L treatment over a three-year time
period. Without avelumab, the total cost for treating patients with mUC was
estimated to be US$70,268,035. The introduction of avelumab increased total
costs by $73,438 (0.10% increase). In a hypothetical Medicare health plan of
30,000,000 beneficiaries, a total of 4,705 patients were estimated to be
eligible for 2L treatment. Without avelumab, the total cost for treating
patients with mUC was estimated to be $292,923,098 from a Medicare perspective;
however, with avelumab, there was an increase of $719,324 (0.25% increase) in
total costs. Results of the sensitivity analyses demonstrated a cost-neutral
impact across all tested scenarios from both perspectives.
CONCLUSION: The BIM estimated that avelumab would have a cost-neutral impact
within a US commercial and a Medicare health plan. Overall, avelumab can be an
affordable and valuable treatment option for patients with locally advanced or
mUC in the 2L setting. These findings demonstrate a consistently favorable
budget impact in both populations. Further studies should be conducted to more
comprehensively assess the clinical and economic implications of adding avelumab
to the treatment armamentarium of 2L mUC. Advancements in the understanding of tumor immunology in urothelial carcinoma
(UC) have led to U.S Food and Drug Administration (FDA) approval of five novel
anti-programmed cell death protein-1/ligand 1 (PD-1/L1) checkpoint inhibitors.
In 2017, the anti-PD-L1 antibody atezolizumab and the anti-PD-1 antibody
pembrolizumab gained approval for use in cisplatin-ineligible patients with
locally advanced and metastatic UC. These approvals were based on single-arm
trials, IMvigor210 (atezolizumab) and KEYNOTE-052 (pembrolizumab). Since then,
additional checkpoint inhibitors, including avelumab, durvalumab, and nivolumab,
have gained approval. Preliminary results suggest additional benefits with
combinations of these agents in both first- and subsequent-line therapies,
inferring a paradigm shift in the future treatment approach in advanced UC.
Ongoing clinical trials will investigate how to utilize predictive biomarkers
for optimal patient selection and to incorporate immunotherapy into earlier
lines of multimodal treatment. In this comprehensive review, we summarize the
evidence supporting the use of checkpoint inhibitors for patients with UC, and
highlight ongoing clinical trials that are investigating novel combinations of
immunotherapy in various disease settings. Five new PD-1/PD-L1 checkpoint inhibitors have been approved for the treatment
of metastatic urothelial carcinoma (UC): pembrolizumab, atezolizumab,
durvalumab, nivolumab, and avelumab. Although cisplatin-based chemotherapy
remains the recommended frontline option for cisplatin-eligible patients with
metastatic UC, immunotherapy is now an available option in the second-line
setting as well as the frontline setting for selected cisplatin-ineligible
patients who are either unable to tolerate chemotherapy or PD-L1-positive. This
review describes the updated clinical efficacy of these checkpoint inhibitors in
the treatment of advanced UC and suggests how they can be sequenced in the
context of available chemotherapeutic options. We performed a systematic review and meta-analysis on the response rates of
patients with treatment-refractory urothelial carcinoma treated with programmed
cell death 1 (PD-1) and programmed death ligand 1 (PD-L1) inhibitors. We
reviewed the literature for prospective studies evaluating PD-1/PD-L1 inhibitors
in refractory urothelial carcinoma patients, which formed the basis for US Food
and Drug Administration approval of 5 different antagonistic antibodies
targeting PD-1 or PD-L1 (atezolizumab, durvalumab, avelumab, nivolumab, and
pembrolizumab). We considered studies examining PD-1/PD-L1-treated patients,
which we identified using the following key terms in the Pubmed, Scopus, Web of
Science, ClinicalTrial.gov, and Cochrane Library databases. Eligible studies
had ≥ 20 patients each and reported response rates, duration of response, and
overall survival (OS). We performed fixed and random-effects meta-analyses to
model the point estimates for objective response rate and complete response. The
median progression-free survival (PFS) and OS for studies reporting these
statistics were evaluated. We found 10 eligible studies that met our inclusion
criteria, providing extractable numerators and denominators for response rates,
PFS, and OS for 1934 patients with metastatic urothelial carcinoma. The
objective response rate was 18% (95% confidence interval, 15-22) for second-line
or later therapies. The random-effects estimate for complete response was 4%
(95% confidence interval, 3-5), including all disease locations and all PD-1 and
PD-L1 inhibitors. Median OS and PFS were < 13 months and 3 months, respectively,
across all studies, irrespective of PD-L1 expression. We found that the
estimated response rates of agents included in this meta-analysis seem to be
more favorable than other salvage therapies. BACKGROUND: Platinum-based chemotherapy is standard-of-care first-line treatment
for advanced urothelial carcinoma. However, progression-free survival and
overall survival are limited by chemotherapy resistance.
METHODS: In a phase 3 trial, we randomly assigned patients with unresectable
locally advanced or metastatic urothelial cancer who did not have disease
progression with first-line chemotherapy (four to six cycles of gemcitabine plus
cisplatin or carboplatin) to receive best supportive care with or without
maintece avelumab. The primary end point was overall survival, assessed among
all patients who underwent randomization (overall population) and among those
with tumors positive for programmed cell death ligand 1 (PD-L1). Secondary end
points included progression-free survival and safety.
RESULTS: Among all 700 patients who underwent randomization, the addition of
maintece avelumab to best supportive care significantly prolonged overall
survival as compared with best supportive care alone (control). Overall survival
at 1 year was 71.3% in the avelumab group and 58.4% in the control group (median
overall survival, 21.4 months vs. 14.3 months; hazard ratio for death, 0.69; 95%
confidence interval [CI], 0.56 to 0.86; P = 0.001). Avelumab also significantly
prolonged overall survival in the PD-L1-positive population; overall survival at
1 year was 79.1% in the avelumab group and 60.4% in the control group (hazard
ratio, 0.56; 95% CI, 0.40 to 0.79; P<0.001). The median progression-free
survival was 3.7 months in the avelumab group and 2.0 months in the control
group in the overall population (hazard ratio for disease progression or death,
0.62; 95% CI, 0.52 to 0.75) and 5.7 months and 2.1 months, respectively, in the
PD-L1-positive population (hazard ratio, 0.56; 95% CI, 0.43 to 0.73). The
incidence of adverse events from any cause was 98.0% in the avelumab group and
77.7% in the control group; the incidence of adverse events of grade 3 or higher
was 47.4% and 25.2%, respectively.
CONCLUSIONS: Maintece avelumab plus best supportive care significantly
prolonged overall survival, as compared with best supportive care alone, among
patients with urothelial cancer who had disease that had not progressed with
first-line chemotherapy. (Funded by Pfizer and Merck [Darmstadt, Germany];
JAVELIN Bladder 100 ClinicalTrials.gov number, NCT02603432.). Conflict of interest statement: Competing interests: ABA has no relationships to
disclose. JAE has no relationships to disclose. JRI has received research
funding from Aileron Therapeutics, ARMO BioSciences, AstraZeneca, BioMed Valley
Discoveries, Bristol Myers Squibb, Calithera Biosciences, Celldex, eFFECTOR
Therapeutics, Genentech/Roche, GlaxoSmithKline, Immunocore, Janssen Oncology,
MedImmune, Merck and Co., Novartis, Pfizer, Phosplatin Therapeutics, Roche, and
TESARO. MA has no relationships to disclose. MSG reports having stocks and other
ownership interests in Caremission and WCCT Global; has received research
funding from AbbVie, Acetylon, Aduro Biotech, Advaxis, Amgen, Array BioPharma,
BeiGene, BioLineRx, Calithera Biosciences, CanBas, Celgene, Celldex, Corcept
Therapeutics, CtyomX Therapeutics, Deciphera, Driver Group, Endocyte, ESSA, Five
Prime Therapeutics, FujiFilm, Genentech/Roche, Gilead Sciences, GlaxoSmithKline,
Halozyme, Hengrui Therapeutics, Iovate, Incyte, Lilly, Lilly/ImClone, MabVax,
Macrogenics, MedImmune, Merck KGaA (Darmstadt, Germany), Merrimack, Millennum,
Minneamrita Therapeutics, Nektar, Novartis, Novita Pharmaceuticals, OncoMed,
Pfizer, Phoenix Biotech, Plexxikon, Proderm IQ, Samumed, Seattle Genetics,
Sirtex Medical, Strategia Therapeutics, Syndax, SynDevRx, TESARO, Tokai
Pharmaceuticals, Tolero Pharmaceuticals, Toray Industries, TRACON Pharma,
Trovagene, and Verastem; and reports patents, royalties or other intellectual
property for patient-on-patient selection for clinical trials. RA has no
relationships to disclose. TG has received research funding from Ferring
Pharmaceuticals. LD has no relationships to disclose. K-WL has received research
funding from Array BioPharma, ASLAN Pharmaceuticals, AstraZeneca/MedImmune, Five
Prime Therapeutics, Green Cross Corp., LSK BioPharma, MacroGenics, Merck KGaA
(Darmstadt, Germany), MSD, Ono Pharmaceutical, Pfizer, and Pharmacyclics. MHT
reports serving as a consultant or advisor for ArQule, Array BioPharma, Bayer,
Blueprint Medicines, Bristol Myers Squibb, Eisai, Loxo, and Novartis; and is a
member of a speaker’s bureau for Bristol Myers Squibb, and Eisai. PS reports
serving as a consultant or advisor for Blueprint Medicines, Eisai, Ellipses
Pharma, Epizyme, Ipsen, Lilly, Loxo, PIQUR Therapeutics, and Plexxikon; and has
received research funding from Blueprint Medicines, Boehringer Ingelheim,
CoBioRes, Eisai, Exelixis, G1 Therapeutics, Lilly, Novartis, PharmaMar, and
Plexxikon. DW reports serving as a consultant or advisor for Merck and Co.; and
has received reimbursement for travel, accommodation and expenses from Merck and
Co. AR has received honoraria from Bristol Myers Squibb, Ipsen, Merck KGaA
(Darmstadt, Germany), MSD, Novartis, and Pfizer; reports serving as a consultant
or advisor for Bristol Myers Squibb, Ipsen, Novartis, Pfizer, and Roche; has
received research funding from Novartis and Pfizer; and has received
reimbursement for travel, accommodation and expenses from Bristol Myers Squibb,
MSD, Novartis, and Pfizer. JM reports employment at EMD Serono Research &
Development Institute, Inc.; a business of Merck KGaA, Darmstadt, Germany. GP
reports employment at EMD Serono, Inc.; a business of Merck KGaA, Darmstadt,
Germany. MR reports employment at EMD Serono Research & Development Institute,
Inc.; a business of Merck KGaA, Darmstadt, Germany. JLG has received research
funding from Astellas/Medivation, Bavarian Nordic, Bristol Myers Squibb, EMD
Serono (a business of Merck KGaA, Darmstadt, Germany), Incyte, Janssen, Merck &
Co, Immunity Bio, and Pfizer. MRP is a member of a speaker’s bureau for Celgene,
Exelixis, Genentech/Roche, and Taiho Pharmaceutical. |
What tissues have been studied by circadian proteomics? | Retina
Liver | The circadian clock in the retina regulates a variety of physiological phenomena
such as disc shedding and melatonin release. Although these events are critical
for retinal functions, it is almost unknown how the circadian clock controls the
physiological rhythmicity. To gain insight into the processes, we performed a
proteomic analysis using 2-DE to find proteins whose levels show circadian
changes. Among 415 retinal protein spots, 11 protein spots showed circadian
rhythmicity in their intensities. We performed MALDI-TOF MS and NanoLC-MS/MS
analyses and identified proteins contained in the 11 spots. The proteins were
related to vesicular transport, calcium-binding, protein degradation,
metabolism, RNA-binding, and protein foldings, suggesting the clock-regulation
of neurotransmitter release, transportation of the membrane proteins,
calcium-binding capability, and so on. We also found a rhythmic phosphorylation
of N-ethylmaleimide-sensitive fusion protein and identified one of the amino
acid residues modified by phosphorylation. These findings provide a new
perspective on the relationship between the physiological functions of the
retina and the circadian clock system. Recent development in the proteomic technologies offers new perspectives in
circadian biology and in particular the possibility to study post-translational
modifications such as phosphorylation and acetylation. Applying in vivo
proteomics on whole liver or on nuclear extracts, we were able to characterize
the rhythmic liver proteome with unprecedented coverage. It allows the
characterization of new rhythmic processes such as protein secretion, ribosome
biogenesis, DNA repair, and polyploidy. In addition, the analysis of rhythmic
post-translational modifications helps to understand the signal pathways
involved and their consequences on hepatic metabolism. |
Is MIS-C or Multisystem Inflammatory syndrome in children a complication of Covid-19? | Is MIS-C or Multisystem Inflammatory Syndrome in children a complication of Covid-19? Yes, it is. | Author information:
(1)Division of Critical Care Medicine, Children's Hospital of Philadelphia,
Philadelphia, Pennsylvania, USA.
(2)Division of Infectious Diseases, Children's Hospital of Philadelphia,
Philadelphia, Pennsylvania, USA.
(3)Perelman School of Medicine, University of Pennsylvania, Philadelphia,
Pennsylvania, USA.
(4)Division of Rheumatology, Children's Hospital of Philadelphia, Philadelphia,
Pennsylvania, USA.
(5)Division of Hematology and Oncology, Children's Hospital of Philadelphia,
Philadelphia, Pennsylvania, USA. Multisystem Inflammatory Syndrome in Children (MIS-C) associated with
Coronavirus Disease 2019 (COVID-19) is a newly recognized condition in which
children with recent SARS-CoV-2 infection present with a constellation of
symptoms including hypotension, multiorgan involvement, and elevated
inflammatory markers. These symptoms and the associated laboratory values
strongly resemble toxic shock syndrome, an escalation of the cytotoxic adaptive
immune response triggered upon the binding of pathogenic superantigens to MHCII
molecules and T cell receptors (TCRs). Here, we used structure-based
computational models to demonstrate that the SARS-CoV-2 spike (S) exhibits a
high-affinity motif for binding TCR, interacting closely with both the α- and
β-chains variable domains' complementarity-determining regions. The binding
epitope on S harbors a sequence motif unique to SARS-CoV-2 (not present in any
other SARS coronavirus), which is highly similar in both sequence and structure
to bacterial superantigens. Further examination revealed that this interaction
between the virus and human T cells is strengthened in the context of a recently
reported rare mutation (D839Y/N/E) from a European strain of SARS-CoV-2.
Furthermore, the interfacial region includes selected residues from a motif
shared between the SARS viruses from the 2003 and 2019 pandemics, which has
intracellular adhesion molecule (ICAM)-like character. These data suggest that
the SARS-CoV-2 S may act as a superantigen to drive the development of MIS-C as
well as cytokine storm in adult COVID-19 patients, with important implications
for the development of therapeutic approaches. Early reports of COVID-19 in pediatric populations emphasized a mild course of
disease with severe cases disproportionately affecting infant and comorbid
pediatric patients. After the peak of the epidemic in New York City, in late
April to early May, cases of severe illness associated with COVID-19 were
reported among mostly previously healthy children ages 5-19. Many of these cases
feature a toxic shock-like syndrome or Kawasaki-like syndrome in the setting of
SARS-CoV-2 positive diagnostic testing and the CDC has termed this presentation
Multisystem Inflammatory Syndrome (MIS-C). It is essential to disseminate
information among the medical community regarding severe and atypical
presentations of COVID-19 as prior knowledge can help communities with
increasing caseloads prepare to quickly identify and treat these patients as
they present in the emergency department. We describe a case of MIS-C in a child
who presented to our Emergency Department (ED) twice and on the second visit was
found to have signs of distributive shock, multi-organ injury and systemic
inflammation associated with COVID-19. The case describes two ED visits by an
11- year-old SARS-CoV-2-positive female who initially presented with fever, rash
and pharyngitis and returned within 48 hours with evidence of cardiac and renal
dysfunction and fluid-refractory hypotension requiring vasopressors and PICU
admission. Author information:
(1)Mucosal Immunology and Biology Research Center, Massachusetts General
Hospital, Boston, MA; Department of Pediatrics, Massachusetts General Hospital,
Boston, MA; Harvard Medical School, Boston, MA. Electronic address:
[email protected].
(2)Department of Pediatrics, Massachusetts General Hospital, Boston, MA; Harvard
Medical School, Boston, MA; Department of Internal Medicine, Massachusetts
General Hospital, Boston, MA.
(3)Harvard Medical School, Boston, MA; Ragon Institute of Massachusetts General
Hospital, Massachusetts Institute of Technology and Harvard, Harvard Medical
School, Cambridge, MA.
(4)Harvard Medical School, Boston, MA; Brigham and Women's Hospital, Department
of Medicine, Renal Division, Boston, MA.
(5)Department of Infectious Diseases, Brigham and Women's Hospital, Boston, MA.
(6)Department of Pediatrics, Massachusetts General Hospital, Boston, MA; Harvard
Medical School, Boston, MA.
(7)Department of Pediatrics, Massachusetts General Hospital, Boston, MA.
(8)Harvard Medical School, Boston, MA.
(9)Mucosal Immunology and Biology Research Center, Massachusetts General
Hospital, Boston, MA; Department of Pediatrics, Massachusetts General Hospital,
Boston, MA.
(10)Department of Internal Medicine, Massachusetts General Hospital, Boston, MA;
Vincent Center for Reproductive Biology, Massachusetts General Hospital, Boston,
MA.
(11)Mucosal Immunology and Biology Research Center, Massachusetts General
Hospital, Boston, MA.
(12)Ragon Institute of Massachusetts General Hospital, Massachusetts Institute
of Technology and Harvard, Harvard Medical School, Cambridge, MA.
(13)Harvard Medical School, Boston, MA; Ragon Institute of Massachusetts General
Hospital, Massachusetts Institute of Technology and Harvard, Harvard Medical
School, Cambridge, MA; Department of Infectious Diseases, Brigham and Women's
Hospital, Boston, MA.
(14)Department of Pediatrics, Massachusetts General Hospital, Boston, MA;
Harvard Medical School, Boston, MA; Department of Internal Medicine,
Massachusetts General Hospital, Boston, MA; Harvard T.H. Chan School of Public
Health, Boston, MA.
(15)Harvard Medical School, Boston, MA; Department of Internal Medicine,
Massachusetts General Hospital, Boston, MA.
(16)Harvard Medical School, Boston, MA; Center for Engineering in Medicine,
Department of Surgery, Boston, MA.
(17)Harvard Medical School, Boston, MA; Vincent Center for Reproductive Biology,
Massachusetts General Hospital, Boston, MA; Department of Obstetrics and
Gynecology, Division of Maternal-Fetal Medicine, Massachusetts General Hospital
Boston, Boston, MA.
(18)Harvard Medical School, Boston, MA; Department of Infectious Diseases,
Brigham and Women's Hospital, Boston, MA.
(19)Mucosal Immunology and Biology Research Center, Massachusetts General
Hospital, Boston, MA; Department of Pediatrics, Massachusetts General Hospital,
Boston, MA; Harvard Medical School, Boston, MA. We report one of the earliest known U.S. cases of multisystem inflammatory
syndrome in children associated with COVID-19 (MIS-C). This adolescent male
presented prior to any known association between COVID-19 and immune mediated
inflammatory syndrome in children. He presented in stable condition and without
significant multisystem involvement. During hospitalization, he developed severe
left ventricular dysfunction and mixed hypovolemic, distributive and cardiogenic
shock. Clinical features overlapped with Kawasaki disease, acute rheumatic
fever, and toxic shock syndrome. After centers in Europe began reporting a
multisystem inflammatory condition in children with COVID-19, the patient's
clinical course and laboratory findings were revisited. He underwent newly
available antibody testing and was diagnosed as one of the first known cases of
MIS-C in the United States. Author information:
(1)Department of Microbiology, Perelman School of Medicine, University of
Pennsylvania, Philadelphia, PA USA.
(2)These authors contributed equally to this work: Elizabeth M. Anderson and
Caroline Diorio.
(3)Immune Dysregulation Frontier Program, Department of Pediatrics, Children's
Hospital of Philadelphia, University of Pennsylvania Perelman School of
Medicine, Philadelphia, PA, USA.
(4)Division of Oncology, Department of Pediatrics, Children's Hospital of
Philadelphia, University of Pennsylvania Perelman School of Medicine,
Philadelphia, PA, USA.
(5)Division of Rheumatology, Department of Pediatrics, Children's Hospital of
Philadelphia, University of Pennsylvania Perelman School of Medicine,
Philadelphia, PA, USA.
(6)School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA
USA.
(7)Institute for Immunology, Perelman School of Medicine, University of
Pennsylvania, Philadelphia, PA, USA.
(8)Department of Systems Pharmacology and Translational Therapeutics, University
of Pennsylvania, Philadelphia, PA, USA.
(9)Division of Infectious Diseases, Department of Pediatrics, Children's
Hospital of Philadelphia, University of Pennsylvania Perelman School of
Medicine, Philadelphia, PA, USA.
(10)Division of Allergy and Immunology, Department of Pediatrics, Children's
Hospital of Philadelphia, University of Pennsylvania Perelman School of
Medicine, Philadelphia, PA, USA.
(11)Department of Pathology and Laboratory Medicine, Children's Hospital of
Philadelphia, University of Pennsylvania Perelman School of Medicine,
Philadelphia, PA, USA.
(12)Penn Center for Research on Coronavirus and Other Emerging Pathogens,
University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA. BACKGROUND: Multisystem inflammatory syndrome in children (MIS-C), also known as
pediatric inflammatory multisystem syndrome, is a new dangerous childhood
disease that is temporally associated with coronavirus disease 2019 (COVID-19).
We aimed to describe the typical presentation and outcomes of children diagnosed
with this hyperinflammatory condition.
METHODS: We conducted a systematic review to communicate the clinical signs and
symptoms, laboratory findings, imaging results, and outcomes of individuals with
MIS-C. We searched four medical databases to encompass studies characterizing
MIS-C from January 1st, 2020 to July 25th, 2020. Two independent authors
screened articles, extracted data, and assessed risk of bias. This review was
registered with PROSPERO CRD42020191515.
FINDINGS: Our search yielded 39 observational studies (n = 662 patients). While
71·0% of children (n = 470) were admitted to the intensive care unit, only 11
deaths (1·7%) were reported. Average length of hospital stay was 7·9 ± 0·6 days.
Fever (100%, n = 662), abdominal pain or diarrhea (73·7%, n = 488), and vomiting
(68·3%, n = 452) were the most common clinical presentation. Serum inflammatory,
coagulative, and cardiac markers were considerably abnormal. Mechanical
ventilation and extracorporeal membrane oxygenation were necessary in 22·2%
(n = 147) and 4·4% (n = 29) of patients, respectively. An abnormal
echocardiograph was observed in 314 of 581 individuals (54·0%) with depressed
ejection fraction (45·1%, n = 262 of 581) comprising the most common aberrancy.
INTERPRETATION: Multisystem inflammatory syndrome is a new pediatric disease
associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)
that is dangerous and potentially lethal. With prompt recognition and medical
attention, most children will survive but the long-term outcomes from this
condition are presently unknown.
FUNDING: Parker B. Francis and pilot grant from 2R25-HL126140. Funding agencies
had no involvement in the study. BACKGROUND: Recently, severe manifestations associated with coronavirus disease
2019 (COVID-19) called multisystem inflammatory syndrome in children (MIS-C)
have been recognized. Analysis of studies for this novel syndrome is needed for
a better understanding of effective management among affected children.
METHODS: An extensive search strategy was conducted by combining the terms
multisystem inflammatory syndrome in children and coronavirus infection or using
the term multisystem inflammatory syndrome in children in bibliographic
electronic databases (PubMed, EMBASE, and CINAHL) and in preprint servers
(BioRxiv.org and MedRxiv.org) following the Preferred Reporting Items for
Systematic Reviews and Metaanalyses guidelines to retrieve all articles
published from January 1, 2020, to July 31, 2020. Observational cross-sectional,
cohort, case series, and case reports were included.
RESULTS: A total of 328 articles were identified. Sixteen studies with 655
participants (3 months-20 years of age) were included in the final analysis.
Most of the children in reported studies presented with fever, gastrointestinal
symptoms, and Kawasaki Disease-like symptoms. Sixty-eight percent of the
patients required critical care; 40% needed inotropes; 34% received
anticoagulation; and 15% required mechanical ventilation. More than two-thirds
of the patients received intravenous immunoglobulin and 49% received
corticosteroids. Remdesivir and convalescent plasma were the least commonly
utilized therapies. Left ventricular dysfunction was reported in 32% of
patients. Among patients presenting with KD-like symptoms, 23% developed
coronary abnormalities and 26% had circulatory shock. The majority recovered; 11
(1.7%) children died.
CONCLUSIONS: This systematic review delineates and summarizes clinical features,
management, and outcomes of MIS-C associated with SARS-CoV-2 infection. Although
most children required intensive care and immunomodulatory therapies, favorable
outcomes were reported in the majority with low-mortality rates. Publisher: CONTEXTE: Depuis avril 2020, de nombreux cas d’enfants présentant une
inflammation généralisée, se trouvant souvent dans un état critique et montrant
des signes d’une infection récente au coronavirus du syndrome respiratoire aigu
sévère 2 (SRAS-CoV-2), ont été signalés. On pense que cet état, désigné depuis
sous le nom de syndrome inflammatoire multisystémique de l’enfant (SIME),
pourrait être une réponse immunitaire tardive au virus de la maladie à
coronavirus 2019 (COVID-19); les patients présentent souvent des manifestations
cardiaques associées à une dysfonction ventriculaire ou à une dilatation des
artères coronaires.
MÉTHODOLOGIE: Nous avons mené un sondage sur les stratégies de prise en charge
du SIME en milieu hospitalier auprès des membres du registre international de la
maladie de Kawasaki, qui sont rattachés à 38 établissements répartis dans 11
pays.
RÉSULTATS: Au total, 56 % des répondants ont déclaré opter pour un traitement
immunomodulateur pour tous les patients présentant un SIME, quelles qu’en soient
les manifestations. Tous les répondants ont déclaré avoir recours à
l’administration d’immunoglobulines par voie intraveineuse, 53 % d’entre eux
utilisant ce traitement chez tous les patients. Les stéroïdes étaient plus
souvent utilisés chez les patients présentant des symptômes cliniques graves ou
ne répondant pas aux immunoglobulines administrées par voie intraveineuse; seule
une minorité de répondants ont déclaré utiliser des stéroïdes chez tous les
patients (14 %). Les répondants utilisaient aussi fréquemment l’acide
acétylsalicylique (91 %), à des doses anti-inflammatoires ou antiplaquettaires.
Ils ont en outre déclaré avoir recours à des anticoagulants en prophylaxie, en
particulier chez les patients présentant un risque élevé de thromboembolie
veineuse, et à une anticoagulothérapie chez les patients présentant des
anévrismes coronaires géants.
CONCLUSIONS: La prise en charge des patients présentant un SIME varie d’un
médecin à l’autre, et les données permettant d’évaluer la supériorité des divers
traitements employés sont insuffisantes; il conviendrait donc de mettre en place
des initiatives de collaboration afin de combler les lacunes des connaissances
et d’optimiser les stratégies thérapeutiques. OBJECTIVE: Multisystem inflammatory syndrome in children (MIS-C) associated with
coronavirus disease (COVID-19) is a rare and challenging diagnosis requiring
early treatment. The diagnostic criteria involve clinical, laboratory, and
complementary tests. This review aims to draw pediatrician attention to this
diagnosis, suggesting early treatment strategies, and proposing a pediatric
emergency care flowchart.
SOURCES: The PubMed/MEDLINE/WHO COVID-19 databases were reviewed for original
and review articles, systematic reviews, meta-analyses, case series, and
recommendations from medical societies and health organizations published
through July 3, 2020. The reference lists of the selected articles were manually
searched to identify any additional articles.
SUMMARY OF THE FINDINGS: COVID-19 infection is less severe in children than in
adults, but can present as MIS-C, even in patients without comorbidities. There
is evidence of an exacerbated inflammatory response with potential systemic
injury, and it may present with aspects similar to those of Kawasaki disease,
toxic shock syndrome, and macrophage activation syndrome. MIS-C can develop
weeks after COVID-19 infection, suggesting an immunomediated cause. The most
frequent clinical manifestations include fever, gastrointestinal symptoms, rash,
mucous membrane changes, and cardiac dysfunction. Elevated inflammatory markers,
lymphopenia, and coagulopathy are common laboratory findings. Supportive
treatment and early immunomodulation can control the intense inflammatory
response and reduce complications and mortality.
CONCLUSIONS: MIS-C associated with COVID-19 is serious, rare, and potentially
fatal. The emergency department pediatrician must recognize and treat it early
using immunomodulatory strategies to reduce systemic injury. Further studies are
needed to identify the disease pathogenesis and establish the most appropriate
treatment. Data on multisystem inflammatory syndrome in children (MIS-C) related to
coronavirus disease-19 (COVID-19) is increasing in the current COVID-19
pandemic. We present a 16 year old male who was hospitalized in July 2020 under
adult medical service due to Kawasaki-like disease symptoms. Diagnosis of MIS-C
related to COVID-19 was established by clinical features, elevated inflammatory
markers, and positive SARS-COV 2 immunoglobulin G. We encourage all clinicians
especially who practice adult medicine to be familiar with signs and symptoms of
MIS-C to avoid delayed diagnosis and complications. Author information:
(1)Science for Life Laboratory, Department of Women's and Children Health,
Karolinska Institutet, Stockholm 17165, Sweden.
(2)Research Unit of Congenital and Perinatal Infections, Bambino Gesù Children's
Hospital, Rome 00165, Italy; Chair of Pediatrics, Department of Systems
Medicine, University of Rome "Tor Vergata", Rome 00133, Italy.
(3)Department of Medicine (Solna), Karolinska University Hospital, Karolinska
Institutet, Stockholm 17176, Sweden.
(4)Research Unit of Congenital and Perinatal Infections, Bambino Gesù Children's
Hospital, Rome 00165, Italy.
(5)Research Unit of Congenital and Perinatal Infections, Bambino Gesù Children's
Hospital, Rome 00165, Italy; Academic Department of Pediatrics, Bambino Gesù
Children's Hospital, IRCCS, Rome 00165, Italy.
(6)Center for Regenerative Medicine, Department of Medicine, Karolinska
Institutet, Stockholm 14186, Sweden.
(7)Department of Medicine (Solna), Karolinska University Hospital, Karolinska
Institutet, Stockholm 17176, Sweden; Department of Immunology, Genetics and
Pathology, Uppsala University and Department of Clinical Genetics, Uppsala
University Hospital, Uppsala 75185, Sweden.
(8)Academic Department of Pediatrics, Bambino Gesù Children's Hospital, IRCCS,
Rome 00165, Italy.
(9)Chair of Pediatrics, Department of Systems Medicine, University of Rome "Tor
Vergata", Rome 00133, Italy; Academic Department of Pediatrics, Bambino Gesù
Children's Hospital, IRCCS, Rome 00165, Italy.
(10)Department of Medicine (Solna), Karolinska University Hospital, Karolinska
Institutet, Stockholm 17176, Sweden; Science for life Laboratory, Department of
Medical Sciences, Uppsala University, Uppsala 75237, Sweden. Electronic address:
[email protected].
(11)Research Unit of Congenital and Perinatal Infections, Bambino Gesù
Children's Hospital, Rome 00165, Italy; Chair of Pediatrics, Department of
Systems Medicine, University of Rome "Tor Vergata", Rome 00133, Italy.
Electronic address: [email protected].
(12)Science for Life Laboratory, Department of Women's and Children Health,
Karolinska Institutet, Stockholm 17165, Sweden; Pediatric Rheumatology,
Karolinska University Hospital, Stockholm 17164, Sweden. Electronic address:
[email protected]. BACKGROUND: The overall severity of cardiac disease secondary to acute
SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2) infection in
children appears to be much lower when compared with adults. However, the newly
described multisystem inflammatory syndrome in children (MIS-C) associated with
coronavirus disease 2019 (COVID-19) has been associated with cardiac
complications.
METHODS: We reviewed the clinical course and cardiac testing results in
pediatric patients hospitalized with MIS-C at 2 large hospital systems in the
New York City metropolitan area over a 3-month period.
RESULTS: Of the 33 patients (median age 2.8 years) in the study cohort, 24 (73%)
had at least one abnormality in cardiac testing: abnormal electrocardiogram
(48%), elevated brain natriuretic peptide (43%), abnormal echocardiogram (30%),
and/or elevated troponin (21%). Electrocardiogram and echocardiogram
abnormalities all resolved by the 2-week outpatient follow-up cardiology visit.
CONCLUSION: While 73% of pediatric patients with MIS-C had evidence of abnormal
cardiac testing on hospital admission in our study, all cardiac testing was
normal by outpatient hospital discharge follow-up. Cardiac screening tests
should be performed in all patients diagnosed with MIS-C given the high rate of
abnormal cardiac findings in our study cohort. The clinical and laboratory features of COVID-19 are reviewed with attention to
the immunologic manifestations of the disease. Recent COVID-19 publications
describe a variety of clinical presentations including an asymptomatic state,
pneumonia, a hemophagocytic lymphohistiocytosis like syndrome, Multisystem
Inflammatory Syndrome in Children (MIS-C) but, also called Pediatric
Inflammatory Multisystem Syndrome-Toxic Shock (PIMS-TS), Kawasaki Disease, and
myocarditis. A common theme amongst multiple reports suggests an overexuberant
autoimmune component of the disease but a common pathophysiology to explain the
variations in clinical presentation has been elusive. Review of the basic
science of other viral induced autoimmune disorders may give clues as to why
immunosuppressive and immunomodulating regimens now appear to have some efficacy
in COVID-19. Review of the immunopathology also reveals other therapies that
have yet to be explored. There is potential use of T cell depleting therapies
and possibly anti-CD20 therapy for COVID-19 and clinical research using these
medications is warranted. Several studies demonstrated that COVID-19 in children is a relatively mild
disease. However, recently a more serious condition characterized by systemic
inflammation with clinical or microbiological evidence of exposure to SARS-CoV-2
has been described. This syndrome is now known as either "Pediatric Inflammatory
Multisystem Syndrome temporally related with COVID-19" (PIMS-TS) (1), or
Multisystem Inflammatory Syndrome in Children (MIS-C) (2) and is currently
considered a rare post-COVID-19 complication which, in a minority of cases, can
lead to death. The signs and symptoms of PIMS-TS are largely overlapping with
the for Kawasaki disease (KD) and toxic shock syndrome (TSS) and are
characterized, by fever, systemic inflammation, abdominal pain and cardiac
involvement. In this study, we describe clinical and immunological
characteristics shared by PIMS-TS, acute rheumatic fever and TSS, in order to
provide hypotheses to direct future clinical and basic research studies. BACKGROUND: To date, there are no comprehensive data on pediatric COVID-19 from
Latin America. This study aims to assess COVID-19 and Multisystem Inflammatory
Syndrome (MIS-C) in Latin American children, to appropriately plan and allocate
resources to face the pandemic on a local and international level.
METHODS: Ambispective multicenter cohort study from 5 Latin American countries.
Children 18 years of age or younger with microbiologically confirmed SARS-CoV-2
infection or fulfilling MIS-C definition were included.
FINDINGS: Four hundred nine children were included, with a median age of 3.0
years (interquartile range 0.6-9.0). Of these, 95 (23.2%) were diagnosed with
MIS-C. One hundred ninety-one (46.7%) children were admitted to hospital and 52
(12.7%) required admission to a pediatric intensive care unit. Ninety-two
(22.5%) patients required oxygen support: 8 (2%) were started on continuous
positive airway pressure and 29 (7%) on mechanical ventilation. Thirty-five
(8.5%) patients required inotropic support. The following factors were
associated with pediatric intensive care unit admission: preexisting medical
condition (P < 0.0001), immunodeficiency (P = 0.01), lower respiratory tract
infection (P < 0.0001), gastrointestinal symptoms (P = 0.006), radiologic
changes suggestive of pneumonia and acute respiratory distress syndrome (P <
0.0001) and low socioeconomic conditions (P = 0.009).
CONCLUSIONS: This study shows a generally more severe form of COVID-19 and a
high number of MIS-C in Latin American children, compared with studies from
China, Europe and North America, and support current evidence of a more severe
disease in Latin/Hispanic children or in people of lower socioeconomic level.
The findings highlight an urgent need for more data on COVID-19 in Latin
America. BACKGROUND: Kawasaki-like syndrome occurring in children during the COVID-19
pandemic has been labelled multisystem inflammatory syndrome in children (MIS-C)
by the CDC and paediatric inflammatory multisystem syndrome temporally
associated with SARS-CoV-2 infection (PIMS-TS) by the ECDC.
CASE REPORT: We report the case of an 18-year-old male patient presenting with a
72-hour history of abdominal pain, fever, erythematous skin rash, vomiting and
diarrhoea. Examination showed he also had shock and he was first thought to have
oedematous cholecystitis. SARS-CoV-2 infection was also diagnosed. He was
admitted to the ICU, and echocardiography showed cardiac dysfunction, with a low
ejection fraction and low cardiac index. High-sensitivity troponin serum levels
were elevated. The patient received inotropic and vasopressor support. As he
fulfilled several criteria for MIS-C/PIMS-TS, he was administered
acetylsalicylic acid, corticosteroids and immunoglobulin, with a good clinical
response.
CONCLUSION: This case emphasizes how this severe presentation of COVID-19 can
easily be misdiagnosed if the clinician is less aware of this syndrome in
younger patients.
LEARNING POINTS: SARS-CoV-2 infection is a diagnostic challenge in some patients
with atypical clinical presentations, who may have MIS-C/PIMS-TS.Physicians
should be aware of this condition when evaluating teenagers and young adults
with COVID-19. The World Health Organization is still revising the epidemiology of multi-system
inflammatory syndrome in children (MIS-C) and the preliminary case definition,
although there is a dearth of robust evidence regarding the clinical
presentations, severity, and outcomes. Researchers, epidemiologists, and
clinicians are struggling to characterize and describe the disease phenomenon
while taking care of the diseased persons at the forefronts. This report tackles
the first case of a 13-year-old Saudi female with the MIS-C mimicking Kawasaki
disease. Her main manifestations were fever, gastrointestinal symptoms, evidence
of organ failure with an increase in inflammatory markers, and a history of
coronavirus disease (COVID-19) infection. She had glucose-6-phosphate
dehydrogenase (G6PD) deficiency and no significant previous history of any
disease. She presented with signs of acute illness: high-grade fever (39.6°C)
for five days accompanied by sore throat, malaise, reduced oral intake,
abdominal pain, diarrhea, skin rash, bilateral non-suppurative conjunctivitis,
and erythematous, cracked lips. Eventually, she died despite aggressive
management based on the Centers for Disease Control and Prevention and the Saudi
Ministry of Health guidelines for COVID-19 management. Based on this case, we
suggest that pediatricians need to be aware of such atypical presentations and
early referral to tertiary care is imperative for further early diagnosis and
management. MIS-C is a rare yet severe and highly critical complication of
COVID-19 infection in pediatrics, leading to serious and life-threatening
illnesses. Knowledge about the wide spectrum of presenting signs and symptoms
and disease severity, including early detection and treatment, is pivotal to
prevent a tragic outcome. INTRODUCTION: Multisystem inflammatory syndrome in children (MIS-C) is a unique
clinical complication of SARS-CoV-2 infection observed in pediatric patients.
COVID-19 is emerging as a potential trigger for the development of diabetes in
children. Here, we report a patient presenting with MIS-C and new onset
diabetes, and discuss the implication and clinical management of these
concomitant conditions.
CASE PRESENTATION: An eight-year-old female presented with hyperglycemia,
ketosis and metabolic acidosis consistent with diabetic ketoacidosis (DKA) in
the setting of fever, rash, respiratory distress, hemodynamic instability,
reduced systolic function with dilation of the left anterior descending artery,
and positive SARS-CoV-2 antibodies suggestive of MIS-C. BACKGROUND: Recently, cases of multisystem inflammatory syndrome in children
(MIS-C) associated with coronavirus disease 2019 (COVID-19) have been reported
worldwide. Negative polymerase chain reaction (RT-PCR) testing associated with
positive serology in most of the cases suggests a postinfectious syndrome.
Because the pathophysiology of this syndrome is still poorly understood,
extensive virological and immunological investigations are needed.
METHODS: We report a series of 4 pediatric patients admitted to Geneva
University Hospitals with persistent fever and laboratory evidence of
inflammation meeting the published definition of MIS-C related to COVID-19, to
whom an extensive virological and immunological workup was performed.
RESULTS: RT-PCRs on multiple anatomical compartments were negative, whereas
anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunoglobulin
A (IgA) and immunoglobulin G (IgG) were strongly positive by enzyme-linked
immunosorbent assay and immunofluorescence. Both pseudoneutralization and full
virus neutralization assays showed the presence of neutralizing antibodies in
all children, confirming a recent infection with SARS-CoV-2. The analyses of
cytokine profiles revealed an elevation in all cytokines, as reported in adults
with severe COVID-19. Although differing in clinical presentation, some features
of MIS-C show phenotypic overlap with hemophagocytic lymphohistiocytosis (HLH).
In contrast to patients with primary HLH, our patients showed normal perforin
expression and natural killer (NK) cell degranulation. The levels of soluble
interleukin (IL)-2 receptor (sIL-2R) correlated with the severity of disease,
reflecting recent T-cell activation.
CONCLUSION: Our findings suggest that MIS-C related to COVID-19 is caused by a
postinfectious inflammatory syndrome associated with an elevation in all
cytokines, and markers of recent T-cell activation (sIL-2R) occurring despite a
strong and specific humoral response to SARS-CoV-2. Further functional and
genetic analyses are essential to better understand the mechanisms of
host-pathogen interactions. INTRODUCTION: Coronavirus disease 2019 (COVID-19) rarely manifests with severe
complications in pediatric patients. An association between COVID-19 and a
Kawasaki-like inflammatory syndrome has recently presented in pediatric
patients.
CASE REPORT: We report a unique case of multisystem inflammatory syndrome in
children presenting with characteristic findings in a child who later developed
cardiogenic shock requiring venoarterial extracorporeal membrane oxygenation.
CONCLUSION: Recognition of these early signs and symptoms facilitates screening
and risk stratification of pediatric COVID-19 cases associated with increased
morbidity. BACKGROUND: Multisystem inflammatory syndrome temporally associated with
COVID-19 (MIS-C) has been described as a novel and often severe presentation of
SARS-CoV-2 infection in children. We aimed to describe the characteristics of
children admitted to Pediatric Intensive Care Units (PICUs) presenting with
MIS-C in comparison with those admitted with SARS-CoV-2 infection with other
features such as COVID-19 pneumonia.
METHODS: A multicentric prospective national registry including 47 PICUs was
carried out. Data from children admitted with confirmed SARS-CoV-2 infection or
fulfilling MIS-C criteria (with or without SARS-CoV-2 PCR confirmation) were
collected. Clinical, laboratory and therapeutic features between MIS-C and
non-MIS-C patients were compared.
RESULTS: Seventy-four children were recruited. Sixty-one percent met MIS-C
definition. MIS-C patients were older than non-MIS-C patients (p = 0.002):
9.4 years (IQR 5.5-11.8) vs 3.4 years (IQR 0.4-9.4). A higher proportion of them
had no previous medical history of interest (88.2% vs 51.7%, p = 0.005).
Non-MIS-C patients presented more frequently with respiratory distress (60.7% vs
13.3%, p < 0.001). MIS-C patients showed higher prevalence of fever (95.6% vs
64.3%, p < 0.001), diarrhea (66.7% vs 11.5%, p < 0.001), vomits (71.1% vs 23.1%,
p = 0.001), fatigue (65.9% vs 36%, p = 0.016), shock (84.4% vs 13.8%, p < 0.001)
and cardiac dysfunction (53.3% vs 10.3%, p = 0.001). MIS-C group had a lower
lymphocyte count (p < 0.001) and LDH (p = 0.001) but higher neutrophil count
(p = 0.045), neutrophil/lymphocyte ratio (p < 0.001), C-reactive protein
(p < 0.001) and procalcitonin (p < 0.001). Patients in the MIS-C group were less
likely to receive invasive ventilation (13.3% vs 41.4%, p = 0.005) but were more
often treated with vasoactive drugs (66.7% vs 24.1%, p < 0.001), corticosteroids
(80% vs 44.8%, p = 0.003) and immunoglobulins (51.1% vs 6.9%, p < 0.001). Most
patients were discharged from PICU by the end of data collection with a median
length of stay of 5 days (IQR 2.5-8 days) in the MIS-C group. Three patients
died, none of them belonged to the MIS-C group.
CONCLUSIONS: MIS-C seems to be the most frequent presentation among critically
ill children with SARS-CoV-2 infection. MIS-C patients are older and usually
healthy. They show a higher prevalence of gastrointestinal symptoms and shock
and are more likely to receive vasoactive drugs and immunomodulators and less
likely to need mechanical ventilation than non-MIS-C patients. IMPORTANCE: To date, no study has characterized the mucocutaneous features seen
in hospitalized children with multisystem inflammatory syndrome in children
(MIS-C) or the temporal association of these findings with the onset of systemic
symptoms.
OBJECTIVE: To describe the mucocutaneous findings seen in children with MIS-C
during the height of the coronavirus disease 2019 (COVID-19) pandemic in New
York City in 2020.
DESIGN, SETTING, AND PARTICIPANTS: A retrospective case series was conducted of
35 children admitted to 2 hospitals in New York City between April 1 and July
14, 2020, who met Centers for Disease Control and Prevention and/or
epidemiologic criteria for MIS-C.
MAIN OUTCOMES AND MEASURES: Laboratory and clinical characteristics, with
emphasis on mucocutaneous findings, of children who met criteria for MIS-C. The
characterization of mucocutaneous features was verified by 2 board-certified
pediatric dermatologists.
RESULTS: Twenty-five children (11 girls [44%]; median age, 3 years [range,
0.7-17 years]) were identified who met definitional criteria for MIS-C; an
additional 10 children (5 girls [50%]; median age, 1.7 years [range, 0.2-15
years]) were included as probable MIS-C cases (patients met all criteria with
the exception of laboratory test evidence of severe acute respiratory syndrome
coronavirus 2 [SARS-CoV-2] infection or known exposure). The results of
polymerase chain reaction tests for SARS-CoV-2 were positive for 10 patients
(29%), and the results of SARS-CoV-2 immunoglobulin G tests were positive for 19
patients (54%). Of the 35 patients, 29 (83%) exhibited mucocutaneous changes,
with conjunctival injection (n = 21), palmoplantar erythema (n = 18), lip
hyperemia (n = 17), periorbital erythema and edema (n = 7), strawberry tongue
(n = 8), and malar erythema (n = 6) being the most common findings. Recognition
of mucocutaneous findings occurred a mean of 2.7 days (range, 1-7 days) after
the onset of fever. The duration of mucocutaneous findings varied from hours to
days (median duration, 5 days [range, 0-11 days]). Neither the presence nor
absence of mucocutaneous findings was significantly associated with overall
disease severity.
CONCLUSIONS AND RELEVANCE: In this case series of hospitalized children with
suspected MIS-C during the COVID-19 pandemic, a wide spectrum of mucocutaneous
findings was identified. Despite their protean and transient nature, these
mucocutaneous features serve as important clues in the recognition of MIS-C. Multisystem inflammatory syndrome in children (MIS-C) is a life-threatening
post-infectious complication occurring unpredictably weeks after mild or
asymptomatic SARS-CoV2 infection in otherwise healthy children. Here, we define
immune abnormalities in MIS-C compared to adult COVID-19 and pediatric/adult
healthy controls using single-cell RNA sequencing, antigen receptor repertoire
analysis, unbiased serum proteomics, and in vitro assays. Despite no evidence of
active infection, we uncover elevated S100A-family alarmins in myeloid cells and
marked enrichment of serum proteins that map to myeloid cells and pathways
including cytokines, complement/coagulation, and fluid shear stress in MIS-C
patients. Moreover, NK and CD8 T cell cytotoxicity genes are elevated, and
plasmablasts harboring IgG1 and IgG3 are expanded. Consistently, we detect
elevated binding of serum IgG from severe MIS-C patients to activated human
cardiac microvascular endothelial cells in culture. Thus, we define
immunopathology features of MIS-C with implications for predicting and managing
this SARS-CoV2-induced critical illness in children. |
Which RNA polymerase transcribes enhancer RNAs? | Analogously to mRNAs, the non-protein-encoding enhancer RNAs are synthesized by RNA Pol II and post-transcriptionally modified by addition of a 5'-cap and a 3'-poly (A) tail. | We have cloned and sequenced a 977bp DNA fragment, pXTU6-2, that represents the
transcription unit for a Xenopus tropicalis U6 RNA gene. This basic repeating
unit is reiterated ca.500-fold per haploid genome. Oocyte injections of pXTU6-2
led to the transcription of a mature-sized U6 RNA that, however, lacked internal
2'-O-methylations. These posttranscriptional modifications of U6 RNA might be
cytoplasmic and could require its association with U4 RNA to be accomplished.
The low alpha- amanitin sensitivity of U6 RNA synthesis in oocytes suggested
that U6 RNA is transcribed by RNA polymerase III, consistent with features of
the U6 RNA molecule which also contains a Box A- like intragenic control region.
Inspection of X. tropicalis, mouse and human U6 DNA upstream sequences revealed
the presence of a TATA box as well as of the proximal and enhancer (octamer
motif) elements contained in snRNA genes transcribed by RNA polymerase II. We
propose that U6 RNAs are synthesized by a specialized transcription complex
consisting of RNA polymerase III and transcription factors, some of which are
very likely shared with RNA polymerase II promoters. U RNAs are highly abundant small nuclear RNAs involved in the processing of
messenger RNA. Most U RNA genes are thought to be transcribed by RNA polymerase
II (pol II). However, evidence has recently been presented that U6 RNA genes are
transcribed by RNA polymerase III (pol III). In the light of these results it
was surprising to find that the 5' flanking region of a mouse U6 RNA gene
includes a perfect copy of the octamer sequence motif, ATTTGCAT, found in many
RNA polymerase II transcription enhancer elements. In the present study we show
that deletion of mouse U6 gene sequences upstream of nucleotide position -217,
including the octanucleotide motif, reduces U6 transcription by 90% when assayed
in Xenopus laevis oocytes, suggesting the presence of a distant control element.
DNase I footprinting of the 5' flanking region of the U6 gene shows protection
of the octanucleotide sequence. Moreover, the 5' flanking sequence from -217 to
-315 can replace the enhancer of a human U2 RNA gene. We therefore conclude that
although U6 RNA genes appear to be transcribed by pol III, they are preceeded by
an enhancer-like element which can functionally substitute for the enhancer of a
pol II-transcribed U RNA gene. To examine the RNA polymerase (EC 2.7.7.6) specificity of RNA
maturation/utilization and transcriptional enhancement, we constructed a
chimeric plasmid (pPolI-CAT) in which a promoter for mouse rRNA gene
transcription was placed adjacent the coding sequences for chloramphenicol
acetyltransferase (CAT; EC 2.3.1.28). A number of other constructs, including
plasmids also containing a murine sarcoma virus enhancer or lacking any natural
eukaryotic promoter sequences, were also prepared. In apparent agreement with
earlier conclusions that an RNA polymerase I transcript can act as a messenger
RNA, transient transfection of mouse L cells with pPolI-CAT yielded both high
levels of transcription from the RNA polymerase I promoter and enzymatically
active CAT protein. However, further examination revealed that CAT protein is
not translated from RNA that begins at the normal rRNA transcription initiation
site. Polysomal RNA is devoid of such RNA and instead consists of CAT-encoding
transcripts that begin elsewhere in the mouse ribosomal DNA (rDNA) region. Since
transcription of these aberrant RNAs is stimulated by the addition of a murine
sarcoma virus enhancer segment, they are probably transcribed by RNA polymerase
II. Transcripts that map to the authentic rRNA start site are not similarly
enhanced. Moreover, unlike the RNAs deriving from the rRNA initiation site,
these aberrant RNAs are more stable and the level of translatable CAT
transcripts is suppressed by inclusion of larger segments of the rDNA promoter
regions. Fortuitously initiated mRNAs are also formed in the absence of any
natural eukaryotic promoter sequence. From these data we conclude that there is
no evidence that normal RNA polymerase I transcription yields functional mRNA
and that transcriptional enhancement appears to be RNA polymerase specific. We used genome-wide sequencing methods to study stimulus-dependent enhancer
function in mouse cortical neurons. We identified approximately 12,000 neuronal
activity-regulated enhancers that are bound by the general transcriptional
co-activator CBP in an activity-dependent manner. A function of CBP at enhancers
may be to recruit RNA polymerase II (RNAPII), as we also observed
activity-regulated RNAPII binding to thousands of enhancers. Notably, RNAPII at
enhancers transcribes bi-directionally a novel class of enhancer RNAs (eRNAs)
within enhancer domains defined by the presence of histone H3 monomethylated at
lysine 4. The level of eRNA expression at neuronal enhancers positively
correlates with the level of messenger RNA synthesis at nearby genes, suggesting
that eRNA synthesis occurs specifically at enhancers that are actively engaged
in promoting mRNA synthesis. These findings reveal that a widespread mechanism
of enhancer activation involves RNAPII binding and eRNA synthesis. Enhancers are cis-regulatory elements that enable precise spatiotemporal
patterns of gene expression during development and are notable for being able to
function at large distances from their target genes. Such regulatory elements
often bypass intervening genes and typically comprise binding sites for multiple
transcription factors that can also be transcribed by RNA polymerase II (Pol II)
to produce noncoding enhancer RNAs (eRNAs). Genome-wide analyses have revealed
chromatin signatures of enhancers, such as the enrichment for monomethylation of
histone H3 lysine 4 (H3K4me1) and the acetylation or methylation of histone H3
lysine 27 (H3K27). Enhancer signatures have been used to describe the
transitions of these regulatory elements from inactive to primed and from
activated to decommissioned states during development. New mutations of enhancer
sequences and of the protein factors regulating enhancer function in human
disease continue to be identified, contributing to a growing class of
'enhanceropathies'. The RNA exosome complex constitutes the major nuclear eukaryotic 3'-5'
exonuclease. Outside of nucleoli, the human nucleoplasmic exosome is directed to
some of its substrates by the nuclear exosome targeting (NEXT) complex. How NEXT
targets RNA has remained elusive. Using an in vivo crosslinking approach, we
report global RNA binding sites of RBM7, a key component of NEXT. RBM7
associates broadly with RNA polymerase II-derived RNA, including pre-mRNA and
short-lived exosome substrates such as promoter upstream transcripts (PROMPTs),
enhancer RNAs (eRNAs), and 3'-extended products from snRNA and
replication-dependent histone genes. Within pre-mRNA, RBM7 accumulates at the 3'
ends of introns, and pulse-labeling experiments demonstrate that RBM7/NEXT
defines an early exosome-targeting pathway for 3'-extended snoRNAs derived from
such introns. We propose that RBM7 is generally loaded onto newly synthesized
RNA to accommodate exosome action in case of available unprotected RNA 3' ends. Enhancers play a crucial role in gene regulation but the participation of
enhancer transcripts (i.e. enhancer RNA, eRNAs) in regulatory systems remains
unclear. We provide a computational analysis on eRNAs using genome-wide data
across 12 mouse tissues. The expression of genes targeted by transcribing
enhancer is positively correlated with eRNA expression and significantly higher
than expression of genes targeted by non-transcribing enhancers. This result
implies eRNA transcription indicates a state of enhancer that further increases
gene expression. This state of enhancer is tissue-specific, as the same enhancer
differentially transcribes eRNAs across tissues. Therefore, the presence of
eRNAs describes a tissue-specific state of enhancer that is generally associated
with higher expressed target genes, surmising as to whether eRNAs have gene
activation potential. We further found a large number of eRNAs contain regions
in which sequences and secondary structures are similar to microRNAs.
Interestingly, an increasing number of recent studies hypothesize that microRNAs
may switch from their general repressive role to an activating role when
targeting promoter sequences. Collectively, our results provide speculation that
eRNAs may be associated with the selective activation of enhancer target genes. Recent work has shown that RNA polymerase II-mediated transcription at distal
cis-regulatory elements serves as a mark of highly active enhancers. Production
of noncoding RNAs at enhancers, termed eRNAs, correlates with higher expression
of genes that the enhancer interacts with; hence, eRNAs provide a new tool to
model gene activity in normal and disease tissues. Moreover, this unique class
of noncoding RNA has diverse roles in transcriptional regulation. Transcribed
enhancers can be identified by a common signature of epigenetic marks by
overlaying a series of genome-wide chromatin immunoprecipitation and RNA
sequencing datasets. A computational approach to filter non-enhancer elements
and other classes of noncoding RNAs is essential to not cloud downstream
analysis. Here we present a protocol that combines wet and dry bench methods to
accurately identify transcribed enhancers genome-wide as well as an experimental
procedure to validate these datasets. Transcriptional enhancers are DNA regulatory elements that are bound by
transcription factors and act to positively regulate the expression of nearby or
distally located target genes. Enhancers have many features that have been
discovered using genomic analyses. Recent studies have shown that active
enhancers recruit RNA polymerase II (Pol II) and are transcribed, producing
enhancer RNAs (eRNAs). GRO-seq, a method for identifying the location and
orientation of all actively transcribing RNA polymerases across the genome, is a
powerful approach for monitoring nascent enhancer transcription. Furthermore,
the unique pattern of enhancer transcription can be used to identify enhancers
in the absence of any information about the underlying transcription factors.
Here, we describe the computational approaches required to identify and analyze
active enhancers using GRO-seq data, including data pre-processing, alignment,
and transcript calling. In addition, we describe protocols and computational
pipelines for mining GRO-seq data to identify active enhancers, as well as known
transcription factor binding sites that are transcribed. Furthermore, we discuss
approaches for integrating GRO-seq-based enhancer data with other genomic data,
including target gene expression and function. Finally, we describe molecular
biology assays that can be used to confirm and explore further the function of
enhancers that have been identified using genomic assays. Together, these
approaches should allow the user to identify and explore the features and
biological functions of new cell type-specific enhancers. Enhancer-derived RNAs (eRNAs) are a group of RNAs transcribed by RNA polymerase
II from the domain of transcription enhancers, a major type of cis-regulatory
elements in the genome. The correlation between eRNA production and enhancer
activity has stimulated studies on the potential role of eRNAs in
transcriptional regulation. Additionally, eRNA has also served as a marker for
global identification of enhancers. Here I review the brief history and
fascinating properties of eRNAs. BACKGROUND: The estrogen receptor (ER) is a ligand-dependant transcription
factor expressed in many breast cancers and is the target of many
endocrine-based cancer therapies. Genome-wide studies have shown that the ER
binds to gene-specific enhancer regions in response to β-estradiol (E2) which
undergo transcription producing noncoding enhancer RNA (eRNA). While eRNAs are
important for transcriptional activation of neighboring genes, the mechanism
remains poorly understood.
RESULTS: Using ChIP-Seq we generate a global profile of thymine DNA glycosylase
(TDG), an ER coactivator that plays an essential role in DNA demethylation, in
response to E2 in the MCF7 breast cancer cell line. Remarkably, we found that in
response to E2 TDG localized to enhancers which also recruit ERα, RNA Pol II and
other coregulators and which are marked by histone modifications indicative of
active enhancers. Importantly, depletion of TDG inhibits E2-mediated
transcription of eRNAs and transcription of ER-target genes. Functionally, we
find that TDG both sensitizes MCF7 cells to tamoxifen-mediated cytostasis and
increases migration and invasion of MCF7 cells.
CONCLUSIONS: Taken together we find that TDG plays a central role in mediating
transcription at a subset of enhancers and governs how MCF7 cells respond to
both estrogenic and anti-estrogenic compounds and may be an effective
therapeutic target. BACKGROUND: Enhancer RNAs (eRNAs) are a group of lncRNAs transcribed from
enhancers, whose regulatory effects on gene expression are an emerging area of
interest. However, the role of eRNAs in regulating trophoblast cells and
unexplained recurrent pregcy loss (URPL) remains elusive.
METHODS: We profiled eRNAs in villi from URPL patients and matched controls by
RNA-seq. Functions of URPL-related eRNAs were further investigated in vitro.
RESULTS: We identified lnc-SLC4A1-1, which was transcribed from an active
enhancer marked with H3K27ac and H3K4me1 and so-called eRNA, highly expressed in
URPL patients. Gain-of-function experiments indicated that lnc-SLC4A1-1
facilitated trophoblast cell migration and apoptosis. Mechanistically, as an
eRNA, lnc-SLC4A1-1 was retained in the nuclei and recruited transcription factor
NF-κB to bind to CXCL8, resulting in increased H3K27ac in the CXCL8 promoter and
subsequent elevation of CXCL8 expression. Activation of CXCL8 exacerbated
inflammatory reactions in trophoblast cells by inducing TNF-α and IL-1β, which
could be blocked by an antagonist of lnc-SLC4A1-1.
INTERPRETATION: These findings indicate that an eRNA, lnc-SLC4A1-1, alters
trophoblast function via activation of immune responses and by regulating the
NF-κB/CXCL8 axis. Our study provides new insights in understanding lncRNA/eRNA
function in pathological pregcy, potentially informing on therapeutic
strategies for URPL. FUND: National Natural Science Foundation of China, Natural
Science Foundation of Jiangsu Province, National Key Research and Development
Program, the Priority Academic Program for the Development of Jiangsu Higher
Education Institutions. Inhibition of transcription caused by DNA damage-impaired RNA polymerase II (Pol
II) elongation conceals a local increase in de novo transcription, slowly
progressing from Transcription Start Sites (TSSs) to gene ends. Although
associated with accelerated repair of Pol II-encountered lesions and limited
mutagenesis, it is still unclear how this mechanism is maintained during
genotoxic stress-recovery. Here we uncover a widespread gain in chromatin
accessibility and preservation of the active H3K27ac mark after UV-irradiation.
The concomitant increase in Pol II escape from promoter-proximal pause (PPP)
sites of most active genes, PROMPTs and enhancer RNAs favors unrestrained
initiation, as evidenced by the synthesis of nascent RNAs including start RNAs.
Accordingly, drug-inhibition of PPP-release replenishes levels of pre-initiating
Pol II at TSSs after UV. Our data show that such continuous engagement of Pol II
molecules ensures maximal transcription-driven repair throughout expressed genes
and regulatory loci. Importantly, revealing this uticipated regulatory layer
of UV-response provides physiological relevant traction to the emerging concept
that Pol II initiation rate is determined by pause-release dynamics. |
Name the three phase 3, randomized, double-blind, placebo-controlled that assessed galcanezumab? | Galcanezumab has been assessed in the phase 3, randomized, double-blind, placebo-controlled EVOLVE-1, EVOLVE-2 and REGAIN studies. | Migraine is a debilitating neurologic disease. People who experience migraine
can have substantial disability, impaired functioning and a decreased quality of
life (QoL). Expert recommendations suggest that people with frequent migraine
attacks or severe impairment related to attacks may benefit from preventive
treatment. Despite these recommendations and the existence of evidence-based
guidelines for the use of preventive medication, many people who are candidates
for preventive therapies do not receive them. Thus, there is still a substantial
unmet need for preventive migraine treatment. Calcitonin gene-related peptide
(CGRP) has a demonstrated role in the pathophysiology of migraine.
Galcanezumab-gnlm (galcanezumab) is a humanized monoclonal antibody that binds
to the CGRP ligand and prevents binding to its receptor. It is administered as a
once-monthly subcutaneous injection. The aim of this review is to present a
comprehensive overview of the existing short- and long-term efficacy and safety
data for galcanezumab in patients with migraine. Data from the phase 3,
randomized, double-blind, placebo-controlled EVOLVE-1, EVOLVE-2 and REGAIN
studies show that galcanezumab treatment for 3 or 6 months results in overall
reduction in mean monthly migraine headache days in patients with episodic
(EVOLVE-1 and EVOLVE-2) and chronic (REGAIN) migraine. Greater proportions of
patients with episodic migraine receiving galcanezumab versus placebo
demonstrated a ≥ 50%, ≥ 75% and 100% response to therapy and reported a lower
level of disability and an improvement in functioning and QoL. Similarly, when
compared with placebo, greater proportions of patients with chronic migraine
treated with galcanezumab demonstrated a ≥ 50% and ≥ 75% response and reported
improved functioning. A 12-month open-label study demonstrated the continued
efficacy of galcanezumab for up to 12 months. In all studies galcanezumab was
well tolerated. In conclusion, data from pivotal studies show that galcanezumab
may fulfill an unmet need in the treatment of patients with migraine who require
preventive therapy. |
Is co-loss of BRCA2-RB1 associated with better prognosis for prostate cancer patients? | No. Co-loss of BRCA2-RB1 in human prostate cancer cells induces an epithelial-to-mesenchymal transition, which is associated with invasiveness and a more aggressive disease phenotype. | PURPOSE: Previous sequencing studies revealed that alterations of genes
associated with DNA damage response (DDR) are enriched in men with metastatic
castration-resistant prostate cancer (mCRPC). BRCA2, a DDR and cancer
susceptibility gene, is frequently deleted (homozygous and heterozygous) in men
with aggressive prostate cancer. Here we show that patients with prostate cancer
who have lost a copy of BRCA2 frequently lose a copy of tumor suppressor gene
RB1; importantly, for the first time, we demonstrate that co-loss of both genes
in early prostate cancer is sufficient to induce a distinct biology that is
likely associated with worse prognosis.
EXPERIMENTAL DESIGN: We prospectively investigated underlying molecular
mechanisms and genomic consequences of co-loss of BRCA2 and RB1 in prostate
cancer. We used CRISPR-Cas9 and RNAi-based methods to eliminate these two genes
in prostate cancer cell lines and subjected them to in vitro studies and
transcriptomic analyses. We developed a 3-color FISH assay to detect genomic
deletions of BRCA2 and RB1 in prostate cancer cells and patient-derived mCRPC
organoids.
RESULTS: In human prostate cancer cell lines (LNCaP and LAPC4), loss of BRCA2
leads to the castration-resistant phenotype. Co-loss of BRCA2-RB1 in human
prostate cancer cells induces an epithelial-to-mesenchymal transition, which is
associated with invasiveness and a more aggressive disease phenotype.
Importantly, PARP inhibitors attenuate cell growth in human mCRPC-derived
organoids and human CRPC cells harboring single-copy loss of both genes.
CONCLUSIONS: Our findings suggest that early identification of this aggressive
form of prostate cancer offers potential for improved outcomes with early
introduction of PARP inhibitor-based therapy.See related commentary by Mandigo
and Knudsen, p. 1784. |
Which drugs were investigated in the ALPHEUS trial? | ALPHEUS study examined if ticagrelor was superior to clopidogrel in reducing periprocedural myocardial necrosis in stable coronary patients undergoing high-risk elective percutaneous coronary intervention (PCI). | BACKGROUND: Percutaneous coronary intervention (PCI)-related myonecrosis is
frequent and can affect the long-term prognosis of patients. To our knowledge,
ticagrelor has not been evaluated in elective PCI and could reduce
periprocedural ischaemic complications compared with clopidogrel, the currently
recommended treatment. The aim of the ALPHEUS study was to examine if ticagrelor
was superior to clopidogrel in reducing periprocedural myocardial necrosis in
stable coronary patients undergoing high-risk elective PCI.
METHODS: The ALPHEUS study, a phase 3b, randomised, open-label trial, was done
at 49 hospitals in France and Czech Republic. Patients with stable coronary
artery disease were eligible for the study if they had an indication for PCI and
at least one high-risk characteristic. Eligible patients were randomly assigned
(1:1) to either ticagrelor (180 mg loading dose, 90 mg twice daily thereafter
for 30 days) or clopidogrel (300-600 mg loading dose, 75 mg daily thereafter for
30 days) by use of an interactive web response system, and stratified by centre.
The primary outcome was a composite of PCI-related type 4 (a or b) myocardial
infarction or major myocardial injury and the primary safety outcome was major
bleeding, both of which were evaluated within 48 h of PCI (or at hospital
discharge if earlier). The primary analysis was based on all events that
occurred in the intention-to-treat population. The trial was registered with
ClinicalTrials.gov, NCT02617290.
FINDINGS: Between Jan 9, 2017, and May 28, 2020, 1910 patients were randomly
assigned at 49 sites, 956 to the ticagrelor group and 954 to the clopidogrel
group. 15 patients were excluded from the ticagrelor group and 12 from the
clopidogrel group. At 48 h, the primary outcome was observed in 334 (35%) of 941
patients in the ticagrelor group and 341 (36%) of 942 patients in the
clopidogrel group (odds ratio [OR] 0·97, 95% CI 0·80-1·17; p=0·75). The primary
safety outcome did not differ between the two groups, but minor bleeding events
were more frequently observed with ticagrelor than clopidogrel at 30 days (105
[11%] of 941 patients in the ticagrelor group vs 71 [8%] of 942 patients in the
clopidogrel group; OR 1·54, 95% CI 1·12-2·11; p=0·0070).
INTERPRETATION: Ticagrelor was not superior to clopidogrel in reducing
periprocedural myocardial necrosis after elective PCI and did not cause an
increase in major bleeding, but did increase the rate of minor bleeding at 30
days. These results support the use of clopidogrel as the standard of care for
elective PCI.
FUNDING: ACTION Study Group and AstraZeneca. |
Which cell secretes the enzyme tryptase? | Degranulation of mast cells (MCs) releases several mediators such as vascular endothelial growth factor (VEGF), chymase, tryptase, histamine, and cytokines. | Mast cells (MCs) are known to participate in a variety of patho-physiological
processes depending largely on the intragranular mediators and the production of
cytokines and chemokines during degranulation. Recently, extracellular vesicles
(EVs) have been implicated important functions for MCs, but the components of
MC-derived EVs have not yet been well-characterized. In this study, we aimed to
identify signatures of proteins, long non-coding RNAs (lncRNAs), and microRNAs
(miRNAs) in EVs derived from resting (Rest-EV) and degranulated (Sti-EV) MCs by
differential ultracentrifugation. Using tandem mass tag (TMT)-based quantitative
proteomics technology and RNA sequencing, we identified a total of 1988
proteins, 397 lncRNAs, and 272 miRNAs in Rest-EV and Sti-EV. The proteins
include common EVs markers (cytoskeletal proteins), MCs markers (FcεRI and
tryptase), and some preformed MCs mediators (lysosomal enzymes) as well. The
global expression profiles of lncRNAs and miRNAs identified, for the first time,
from Rest-EV and Sti-EV, strongly suggest a potential regulatory function of
MC-derived EVs. We have also performed Western blotting and qRT-PCR analysis to
further verify some of the proteins, lncRNAs, and miRNAs identified from Rest-EV
and Sti-EV. Our findings will help to elucidate the functions of MC-derived EVs,
and provide a reference dataset for future translational studies involving
MC-derived EVs. BACKGROUND: Waldenström macroglobulinemia (WM) is a subset of lymphoplasmacytic
lymphoma (LPL) with bone marrow (BM) involvement and an IgM monoclonal
gammopathy of any level. We aimed to identify the clinical, laboratory, and BM
findings of patients with WM and to evaluate the usefulness of CD154 for the
diagnosis and prognosis of WM.
METHODS: We reviewed the medical records and BM studies and/or flow cytometric
immunotyping of 31 patients with untreated WM. Semiquantitative
immunohistochemistry (CD20, CD138, tryptase, and CD154) of BM was performed.
RESULTS: Only six patients presented with symptoms of hyperviscosity syndrome.
Eleven patients had solid cancer and/or another hematologic maligcy. Mast
cells (MC) increased in all samples, with some in close contact with tumor
cells. Tryptase-positive MC (17.1/ high-power fields [HPF], 1.2-72.0/HPF) and
CD154-positive MC (8.6/HPF, 0.1-31.1/HPF) were observed. The high CD154-positive
MC (≥8.6/HPF) group showed a lower overall five-year survival rate than the low
CD154-positive MC (<8.6/HPF) group (71.9% vs. 100.0%; P=0.012). Flow cytometric
immunophenotyping of BM aspirates showed increased B lymphocytes and plasma
cells with a normal phenotype (CD138⁺/CD38⁺/CD19⁺/CD45⁺/CD56⁻).
CONCLUSIONS: Approximately one third of WM patients showed other maligcies
and all patients had increased MC. Immunohistochemistry and flow cytometric
immunophenotyping are useful for diagnosing WM, and increased CD154-positive MC
can indicate poor prognosis. |
What disease does BCG immunotherapy used to treat? | Bacillus Calmette-Guérin (BCG) immunotherapy is used for treatment of bladder cancer. | The results of various in vitro analyses indicate there is an active immune
response against antigens associated with human maligcies. This immune
response apparently can be augmented by nonspecific immunologic stimulates such
as BCG. These agents are effective for destroying tumor when injected locally
into intracutaneous disease but are not as effective for subcutaneous disease.
Preliminary clinical trials indicated that immune stimulants are effective when
administered systemically. The effect is only minimal for diseminated disease,
but the therapeutic benefit is clearly augmented for patients with a minimal
residual tumor burden, such as those patients with metastases to regional lymph
nodes. Thus immunotherapy is a systemically active mode of therapy. Its toxicity
is minimal, and it appears to be effective in a wide spectrum of the disease.
However, immunotherapy is not effective for a large residual tumor burden;
consequently it must be used in combination with other modes of treatment such
as irradiation therapy or chemotherapy. Early experiences with BCG immunotherapy
for maligt melanoma and C. parvum for oat cell carcinoma are encouraging. It
is remarkable that a nonspecific immunologic stimulant does, in fact, have this
effect. Immunotherapy experiments in animals suggest that in order to achieve
maximal benefit. BCG must have close contact with tumor cells or must be
combined with a tumor-associated antigen. If these principles are true for man,
it would seem that improvements for nonspecific immunotherapy in human neoplasms
would be further augmented if a tumor-related antigen could be extracted from
human tumours and combined with a nonspecific immunologic stimulant. Despite current surgical therapy, about 80 per cent of patients with maligt
melanoma metastatic to lymph nodes succumb to systemic metastatic disease. To
determine if postoperative adjuvant immunization with BCG was an effective
systemic treatment in these patients with microscopic subclinical metastatic
disease, the clinical course of 42 patients treated by operation alone was
compared with that of 84 treated by operation and BCG. At two years, the
incidence of metastasis in BCG-treated patients was half that of the control
group. BCG was more effective in patients with a smaller tumor burden at the
time of initial surgical treatment. In patients receiving BCG adjuvant therapy,
90 per cent with microscopic disease in one lymph node appeared free of disease
as compared to 40 per cent with macroscopic disease in multiple nodes. In
patients with recurrences, an immunotherapeutic effect was demonstrated by a
delay of six months in the time to recurrence. Thus, BCG immunotherapy appears
to have an inhibiting effect on the "micrometastases" of maligt melanoma. Over the past 7 years, 151 patients with maligt melanoma have been treated
with BCG immunotherapy alone or as an adjunct to surgical therapy. Direct
injection of metastatic melanoma lesions limited to skin resulted in 90%
regression of injected lesions and 17% regression of uninjected lesions in
immunocompetent patients. Approximately 25% of these patients remained free of
disease for 1 to 6 years. Direct injections of BCG into nodules of patients with
subcutaneous or visceral metastases resulted in a lower incidence of local
control and no long term survivors. Attempts to improve the results of
immunotherapy in these patients by palliative surgical resection of large
metastatic lesions to lower tumor burden followed by BCG immunotherapy
significantly improved the results although many patients still developed
recurrent disease. Early results of a clinical trial combining BCG immunotherapy
with regional lymphadenectomy in patients with melanoma metastatic to lymph
nodes have been encouraging and promising. Further controlled clinical trials
are necessary to elucidate the role of BCG in immunotherapy. However, since BCG
is but one of a number of potential immunologic adjuvants, even more effective
immunotherapy will be possible as further knowledge of the interactions of
cellular and humoral immunity is acquired. Initial adjuvant immunotherapy trials have demonstrated a greater disease-free
interval in patients treated with bacille Calmette-Guérin (BCG) compared with
historical controls. In this study 149 patients at high risk of recurrence after
surgical treatment of local or regional maligt melanoma were given BCG for 2
years and were followed up for a median of 28 months from the start of
immunotherapy. The 36 patients in the comparison group had a higher rate of
recurrence than the patients treated with BCG, and the rate in the treatment
group was close to that reported from a similar study at the University of
California at Los Angeles. The relatively long disease-free interval for the
high-risk comparison patients in this study suggests that the control groups at
other centres may have included patients with unrecognized additional risk. The
rates of survival in the Canadian treatment group were also comparable to those
reported by other centres. However, reports of a favourable BCG-mediated pattern
of recurrence could not be confirmed. Therefore, the routine use of adjuvant BCG
immunotherapy is not recommended. Fifty-one patients with confirmed bladder cancer have enrolled in a prospective
evaluation of BCG immunotherapy. Following resection of existing tumors,
patients were stratified according to tumor grade and number of previous
recurrences and randomly assigned to control or BCG treatment groups.
Immunotherapy consisted of six weekly administrations of Pasteur strain BCG
using 120 mg intravesically and 5 mg percutaneously. Immunotherapy side effects
were minimal and no patient required postponement of BCG treatments. Eleven
control (46%) compared with five (22%) BCG-treated patients had tumor recurrence
(P = 0.078, chi 2). Prolongation of the disease-free interval with BCG treatment
was significantly at the P = 0.016 level by Wilcoxon analysis. Four control and
two BCG-treated patients had multiple recurrences. Comparing total episodes of
recurrence, nineteen of 79 (24%) control and eight of 85 (7%) BCG group
cystoscopic examinations revealed tumor (P = 0.006, chi 2). Immunologic
correlates of response to immunotherapy were not statistically significant since
only five BCG-treated patients had tumor recurrence. However, four of these five
patients evidenced impaired LIF response to PPD at the time of tumor recurrence,
and impairment of skin test reactivity and BCG humoral antibody response were
more commonly seen in this subgroup of patients. Prior to the advent of BCG immunotherapy, bladder carcinoma in situ often
progressed to muscle invasion. Intravesical chemotherapy completely eradicates
the disease in 50% of patients, but fewer than 20% remain disease free after 5
years. Complete responses have been reported in 70% or more of BCG treated
patients, nearly two-thirds of which are durable. Controversy over the optimal
induction and maintece regimens for BCG immunotherapy remain, but SWOG
investigators have demonstrated that complete response rates can be increased
from the expected 73% to 87% with just three additional BCG instillations given
at 3 months. In complete responders, maintece BCG using three weekly
treatments at 6-month intervals improves long-term complete response rates from
65% to nearly 90%. Caution must be exercised to avoid serious side effects. Intravesical therapy has been used in the management of superficial transitional
cell carcinoma (TCC) of the urinary bladder (i.e., Ta, Tl, and carcinoma in
situ) with specific objectives which include treating existing/residual tumor,
preventing recurrence of tumor, preventing disease progression, and prolonging
survival. The initial clinical stage and grade remain the main determit
factors in survival irrespective of the treatment. Presently, bacillus
Calmette-Guerin (BCG) immunotherapy remains the most effective treatment and
prophylaxis for TCC (Ta, Tl, CIS) and has positive outcomes on tumor recurrence
rate, disease progression, and prolongation of survival. Prostatic urethral
mucosal involvement with bladder cancer can be effectively treated with BCG
intravesical immunotherapy-it has demonstrated a reduction in tumor recurrence
rates, but has had no positive impact on disease progression or prolongation of
survival. Interferons, keyhole-limpet hemocyanin (KLH), bropirimine, and
PHOTOFRIN-photodynamic therapy (PDT) are under investigation in the management
of TCC and early results are encouraging. This comprehensive review highlights
recent developments in intravesical therapy of bladder cancer and summarizes the
mechanisms of action of BCG, and the important role of intravesical BCG
immunotherapy and other immunotherapeutic agents in the therapy and prophylaxis
of superficial TCC of the urinary bladder. Side-effects are commonly manifested during intravesical Bacillus
Calmette-Guérin (BCG) immunotherapy of superficial bladder cancer. This often
causes delays or interruptions of the instillations and consequently reduces the
efficacy of treatment. Treatment strategies aimed at reducing the side-effects
of BCG immunotherapy while maintaining efficacy are currently being considered
in the search for an optimal treatment regimen. The following two approaches to
BCG immunotherapy were investigated at the Department of Urology of Padova
University by specific Phase II and III trials designed to evaluate the
possibility of reducing BCG-related side-effects without compromising
therapeutic efficacy: (1) by reducing the dose of BCG per instillation
'low-dose' regimen, (2) by delaying the interval of the instillations
'slow-rate' regimen. The primary role of immunotherapy for bladder cancer is to treat superficial
transitional cell carcinomas (ie, carcinoma in situ, Ta, and T1). Immunotherapy
in the form of bacille Calmette-Guérin (BCG), interferon, bropirimine, keyhole
limpet hemocyanin, and gene therapy is intended to treat existing or residual
tumor, to prevent recurrence of tumor, to prevent progression of disease, and to
prolong survival of patients. Presently, BCG is commonly used and is the most
effective immunotherapeutic agent against superficial transitional cell
carcinoma. Data support that BCG has a positive impact on tumor recurrence,
disease progression, and survival. Proper attention to maintece schedules,
route of administration, dosing, strains, and viability is essential to obtain
the maximum benefits of BCG immunotherapy. This review highlights and summarizes
the recent advances concerning immunotherapy, with special emphasis on BCG
therapy for transitional cell carcinoma. The advantage of BCG immunotherapy over intravesical chemotherapy in superficial
bladder cancer has been most apparent in patients with carcinoma in situ (CIS),
where complete response is increased from 50% to more than 70% and the
proportion of patients remaining disease free for 5 years is increased from 20%
to 40%. Similar advantages have been reported using suboptimal BCG treatment
schedules in patients with recurrent stage Ta, T1 tumours. BCG provides long
term protection from tumour recurrence and, unlike chemotherapy, reduces tumour
progression. The observed relative increased sensitivity of CIS to BCG and the
occasional failure of BCG to demonstrate significant superiority over mitomycin
C in the prevention of tumour appear to be related to the use of suboptimal BCG
treatment schedules. With maintece BCG using 3 weekly instillations at 6
month intervals, patients with papillary tumours fare even better than patients
with CIS, and tumour progressio is even further reduceld. Chemotherapy is
appropriate for patients who are at very low risk of tumour progression and
those who fail to respond to BCG, but overall the results of BCG immunotherapy
are superior for patients with either CIS or Ta, T1 transitional cell carcinoma. BACKGROUND: Intravesical immunotherapy with Mycobacterium bovis (M. bovis)
bacillus Calmette-Guerin (BCG) is the current standard of care against
superficial, high-grade transitional cell carcinoma (TCC) of the urinary bladder
(carcinoma in situ and pathologic T1, grade 3 disease). However, individual
patient outcome is barely predictable because of the lack of serum markers.
Consequently, progression to muscle-invasive bladder cancer and critical delay
of treatments (such as neoadjuvant combination chemotherapy and/or radical
cystectomy) often occur. The objectives of this study were to identify a marker
for measuring the BCG-induced immune response and to predict the outcomes and
potential improvements of BCG immunotherapy.
METHODS: Because host immunoresponse mediates BCG activity, the authors screened
a combinatorial random peptide library on the circulating pool of
immunoglobulins (Igs) purified from an index patient after successful BCG
immunotherapy to identify the corresponding target antigen(s).
RESULTS: An immunogenic peptide motif was selected, isolated, and validated from
M. bovis BCG heat-shock protein 65 (HSP-65) as a domit epitope of the humoral
response to treatment. Increasing IgA and IgG anti-HSP-65 titers specifically
predicted a positive patient outcome in a cohort of patients with bladder cancer
relative to several cohorts of control patients.
CONCLUSIONS: The current results indicated that antibody production against M.
bovis BCG HSP-65 can serve as a serologic marker for the predictive outcome of
BCG immunotherapy. Subsequent studies will determine the value of this candidate
marker to modify BCG-based treatment for individual patients with bladder
cancer. Intravesical Mycobacterium bovis bacillus Calmette-Guérin (BCG) immunotherapy is
a highly effective treatment for carcinoma in situ of the bladder, as well as
high-risk nonmuscle invasive urothelial carcinoma of the bladder. Despite over
30 years of clinical experience with BCG, the therapy's mechanism has remained
enigmatic. Observations regarding the role of neutrophils in BCG immunotherapy
have led to exciting discoveries regarding the potential role of tumor necrosis
factor-related apoptosis-inducing ligand (TRAIL) in creating the therapeutic
benefit of BCG immunotherapy. In this paper, we will review the scope of the
disease, highlight our understanding of the role for BCG in urothelial carcinoma
of the bladder, explain the recent discoveries regarding the role of neutrophils
and TRAIL in therapy, and theorize on potential future areas of research. WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: The administration of
Bacillus Calmette-Guérin (BCG) immunotherapy has become the standard of care for
high-grade non-muscle invasive bladder cancer (NMIBC) and carcinoma in-situ
(CIS) in terms of prevention of recurrence and progression. While most agree on
a 6 week induction cycle, various maintece schedules (if any at all) have
been implemented without a unifying consensus. This review assesses the
historical emergence of BCG immunotherapy, beginning with its discovery as a
vaccinatin for tuberculosis to its effect on the host immune system and
potential therapeutic benefits for various oncologic conditions. The data
establishing BCG immunotherapy as the standard of care for high-grade NMIBC and
CIS over other bladder instillation modalities is presented in addition to the
effect maintece BCG therapy has on sustaining the immuno-protective effect.
Bacillus Calmette-Guérin (BCG) immunotherapy is currently the most effective
treatment of non-muscle invasive bladder cancer and one of the most successful
applications of immunotherapy to the treatment of cancer. This review summarises
the history and development of BCG as a modern cancer treatment, appraises
current optimal application of BCG immunotherapy in bladder cancer, discusses
promising new therapies closely related to BCG, and briefly explores the
possibility that BCG or related treatments may have an application in other
urological maligcies. BCG is a nonspecific stimulant to the
reticuloendothelial system and induces a local inflammatory response with the
infiltration of granulocytes followed by macrophages and lymphocytes,
particularly helper T cells. The initial BCG controlled trial showed a
statistically significant reduction in tumour recurrence and found the advantage
increased with duration of follow-up. Similar results were reported in much
higher risk patients in an independent concurrent study. Follow-up suggested
that a single 6-week course of intravesical BCG provided long-term protection
(up to 10 years) from tumour recurrence and even reduced disease progression.
While induction BCG (six weekly instillations) reduced recurrence, progression
and mortality at 10 years, this advantage was lost by 15 years, and patients
remained at high risk for progression without the use of maintece BCG. In a
meta-analysis by the Cochrane group, induction BCG was found to be markedly
superior to mitomycin C in high-risk patients but not in low-risk patients.
Additionally, the National Comprehensive Cancer Network guidelines lists the use
of intravesical BCG as preferred therapy, citing Category 1 data for high-grade
Ta, all T1, and any Tis tumours. Maintece BCG therapy may be the most
important advance in BCG treatment of bladder cancer since the initial
introduction. The risk of tumour recurrence and disease progression is life-long
in most patients, but the immune stimulation induced by BCG wanes with time.
Logarithmic dose reduction of BCG in patients with increasing side-effects will
typically prevent escalation of toxicity. Simple dose reduction, appropriate
antibiotics, and understanding treatment contraindications have greatly
increased the safety of BCG. The 3-week maintece schedule for 3 years has
been evaluated in randomised clinical trials and appears to be the current
optimal treatment. With the success achieved in bladder cancer and the relative
safety and economy of BCG, consideration should be given to further research for
its effectiveness in other genitourinary maligcies. BACKGROUND: High risk of recurrence/progression bladder tumours is treated with
Bacillus Calmette-Guérin (BCG) immunotherapy after complete resection of the
tumour. Approximately 75% of these tumours express the uncommon carbohydrate
antigen sialyl-Tn (Tn), a surrogate biomarker of tumour aggressiveness. Such
changes in the glycosylation of cell-surface proteins influence tumour
microenvironment and immune responses that may modulate treatment outcome and
the course of disease. The aim of this work is to determine the efficiency of
BCG immunotherapy against tumours expressing sTn and sTn-related antigen
sialyl-6-T (s6T).
METHODS: In a retrospective design, 94 tumours from patients treated with BCG
were screened for sTn and s6T expression. In vitro studies were conducted to
determine the interaction of BCG with high-grade bladder cancer cell line
overexpressing sTn.
RESULTS: From the 94 cases evaluated, 36 had recurrence after BCG treatment
(38.3%). Treatment outcome was influenced by age over 65 years (HR=2.668;
(1.344-5.254); P=0.005), maintece schedule (HR=0.480; (0.246-0.936); P=0.031)
and multifocality (HR=2.065; (1.033-4.126); P=0.040). sTn or s6T expression was
associated with BCG response (P=0.024; P<0.0001) and with increased
recurrence-free survival (P=0.001). Multivariate analyses showed that sTn and/or
s6T were independent predictive markers of recurrence after BCG immunotherapy
(HR=0.296; (0.148-0.594); P=0.001). In vitro studies demonstrated higher
adhesion and internalisation of the bacillus to cells expressing sTn, promoting
cell death.
CONCLUSION: s6T is described for the first time in bladder tumours. Our data
strongly suggest that BCG immunotherapy is efficient against sTn- and
s6T-positive tumours. Furthermore, sTn and s6T expression are independent
predictive markers of BCG treatment response and may be useful in the
identification of patients who could benefit more from this immunotherapy. It is nearly 40 years since Bacillus Calmette-Guérin (BCG) was first used as an
immunotherapy to treat superficial bladder cancer. Despite its limitations, to
date it has not been surpassed by any other treatment. As a better understanding
of its mechanism of action and the clinical response to it have evolved, some of
the questions around optimal dosing and treatment protocols have been answered.
However, its potential for toxicity and failure to produce the desired clinical
effect in a significant cohort of patients presents an ongoing challenge to
clinicians and researchers alike. This review summarizes the evidence behind the
established mechanism of action of BCG in bladder cancer, highlighting the
extensive array of immune molecules that have been implicated in its action. The
clinical aspects of BCG are discussed, including its role in reducing recurrence
and progression, the optimal treatment regime, toxicity and, in light of new
evidence, whether or not there is a superior BCG strain. The problems of
toxicity and non-responders to BCG have led to development of new techniques
aimed at addressing these pitfalls. The progress made in the laboratory has led
to the identification of novel targets for the development of new
immunotherapies. This includes the potential augmentation of BCG with various
immune factors through to techniques avoiding the use of BCG altogether; for
example, using interferon-activated mononuclear cells, BCG cell wall, or BCG
cell wall skeleton. The potential role of gene, virus, or photodynamic therapy
as an alternative to BCG is also reviewed. Recent interest in the immune check
point system has led to the development of monoclonal antibodies against
proteins involved in this pathway. Early findings suggest benefit in metastatic
disease, although the role in superficial bladder cancer remains unclear. Bladder cancer is a common maligt disease, with non-muscle-invasive bladder
cancer (NMIBC) representing the majority of tumors. This cancer subtype is
typically treated by transurethral resection. In spite of treatment, up to 70%
of patients show local recurrences. Intravesical BCG (Bacillus Calmette-Guerin)
immunotherapy has been widely used to treat NMIBC, but it fails to suppress
recurrence of bladder tumors in up to 40% of patients. Therefore, the
development of prognostic markers is needed to predict the progression of
bladder cancer and the efficacy of intravesical BCG treatment. This study
demonstrates the effectiveness of an E2F4 signature for prognostic prediction of
bladder cancer. E2F4 scores for each sample in a bladder cancer expression
dataset were calculated by summarizing the relative expression levels of E2F4
target genes identified by ChIP-seq, and then the scores were used to stratify
patients into good- and poor-outcome groups. The molecular signature was
investigated in a single bladder cancer dataset and then its effectiveness was
confirmed in two meta-bladder datasets consisting of specimens from multiple
independent studies. These results were consistent in different datasets and
demonstrate that the E2F4 score is predictive of clinical outcomes in bladder
cancer, with patients whose tumors exhibit an E2F4 score >0 having significantly
shorter survival times than those with an E2F4 score <0, in both
non-muscle-invasive, and muscle-invasive bladder cancer. Furthermore, although
intravesical BCG immunotherapy can significantly improve the clinical outcome of
NMIBC patients with positive E2F4 scores (E2F4>0 group), it does not show
significant treatment effect for those with negative scores (E2F4<0 group).
IMPLICATIONS: The E2F4 signature can be applied to predict the
progression/recurrence and the responsiveness of patients to intravesical BCG
immunotherapy in bladder cancer. A handful of therapeutic procedures are used to treat maligcies of the
urinary tract, most frequently intravesical immunotherapy or chemotherapy, but
also neoadjuvant systemic chemotherapy. These treatment modalities produce
morphological changes in the urothelium that can be mistaken for carcinoma; in
particular, these therapies frequently mimic urothelial carcinoma in situ (CIS)
urothelial dysplasia or true invasive neoplasia. Drugs such as mitomycin C used
after transurethral resection of bladder tumour to reduce recurrences, bacillus
Calmette-Guérin (BCG) intravesical immunotherapy to treat high-risk
non-muscle-invasive bladder cancer and urothelial CIS and platin-based systemic
chemotherapy to improve postcystectomy disease-specific survival are examples of
therapy-related atypia seen in the urinary tract. To complicate the
pathologist's life, a number of systemic drugs in use to treat other diseases,
such cyclophosphamide, used to treat some autoimmune disorders or certain
haematological maligcies or, in the case of anaesthetics, ketamine, used
increasingly as an illegal recreational drug, may produce similarly relevant
atypical changes in the urothelium, and therefore need to be differentiated from
intraepithelial neoplasia. Other less frequent procedures, such as photodynamic
and laser therapy or the newer gene therapy to treat urothelial neoplasia,
remain experimental. An immunohistochemical approach to reactive urothelium
versus carcinoma in situ using p53, cytokeratin 20 and CD44 is also valid in the
post-therapy setting. The pathologist should be aware of these novelties, as he
or she plays a crucial role in evaluating treatment efficacy, but at the same
time needs to avoid misdiagnosing secondary atypia as intraepithelial neoplasia. Bladder cancer arises from the epithelial lining of the urinary bladder, and it
is known as transitional cell carcinoma (TCC). Tobacco smoking is the main known
contributor to urinary bladder cancer. However thirty percent of bladder tumors
probably result from occupational exposure in the workplace to carcinogens.
Immunotherapy by intravesicular delivery of Bacillus Calmette–Guérin (BCG) is
used to treat and prevent the recurrence of superficial bladder cancer.
Successful BCG immunotherapy for bladder cancer is associated with proper
induction of T helper (Th)1 immunity. In bladder cancer patients after
intravesicular BCG, urine was found to contain high levels of IP-10, and
Interferon (IFN)-γ. TCC and endothelial cell lines were able to secrete IP-10 in
response to BCG or IFN stimulation in vitro. Furthermore intravesicular BCG
induces a cytokine-rich urinary microenvironment that is inhibitory to human
endothelial cells and it is anti-angiogenetic by the induction of Th1
chemokines. Other studies suggest that therapeutic strategies involving Th1
induction and Th2 dampening may improve responses to immunotherapy. Further
studies are needed to evaluate the IP-10 in circulation, and urine, as
prognostic marker of bladder cancer patients, also in relation to BCG
immunotherapy Intravesical immunotherapy, chemotherapy, and neoadjuvant systemic chemotherapy
are among the most frequent therapeutic procedures to treat maligcies of the
urinary bladder. These treatment modalities produce reactive morphologic changes
in the urothelium that can mimic urothelial carcinoma in situ, urothelial
dysplasia or true invasive urothelial neoplasia. Mitomycin C used after
transurethral resection of bladder tumor to reduce recurrences, BCG intravesical
immunotherapy to treat high risk non-muscle invasive bladder cancer and
urothelial carcinoma in situ, and platinum-based systemic chemotherapy to
improve post-cystectomy disease-specific survival some of the causes of therapy
related atypia in urinary bladder. In addition, a number of systemic drugs in
use to treat other systemic diseases, such as cyclophosphamide used to treat
certain auto-immune disorders or hematologic maligcies, or the anesthetics
ketamine increasingly used as illegal recreational drug, may produce similarly
relevant atypical changes in the urothelium, and therefore, need to be
differentiated from intraepithelial neoplasia. Immunohistochemical approach to
reactive urothelium from CIS using CK20, p53, and CD44 may also be of utility in
the pos-therapy scenario. PURPOSE OF REVIEW: There is a significant unmet need for efficacious second-line
treatment options for patients who have failed bacillus Calmette-Guerin (BCG)
therapy for nonmuscle invasive urothelial carcinoma (NMIBC). Recent advances in
our understanding of systemic immunotherapy have transformed the management of
advanced urothelial carcinoma and have led to the development of multiple novel
agents. Using this insight, these agents are now being investigated for use in
NMIBC.
RECENT FINDINGS: Although BCG has been used to treat high-risk NMIBC for
decades, new applications of immunotherapy include the use of exogenous
cytokines to boost immune response, vaccines to activate the immune system
against specific tumor-associated antigens, intravesical agents that cause
generalized local inflammation, and targeted antibodies against proteins on the
surface of immune checkpoint inhibitors. Although most of these agents are still
being investigated in clinical trials and are not yet considered standard of
care, they hold significant promise in the treatment of patients with high-risk
NMIBC.
SUMMARY: The use of immunotherapy has significantly improved survival outcomes
in advanced urothelial carcinoma. Based on rapid advances in our understanding
of the immune system and tumor biology, these agents are also poised to alter
the therapeutic landscape for NMIBC dramatically as clinical trials are
completed. Bacillus Calmette-Guérin (BCG) immunotherapy for bladder cancer has been used
since 1976 when the first evidence of its ability to lower recurrence and
progression rates was published. Today, BCG immunotherapy is the choice of care
for high-grade non-muscle invasive bladder cancer (NMIBC) after transurethral
resection. This article presents indications and procedure of BCG instillations,
and outlines the effects on recurrence and progression of NMIBC. The BCG-induced
immunity in NMIBC is not yet fully understood. Animal studies point towards BCG
inducing specific tumour immunity. We describe the current knowledge of how this
immunity is induced, from internalization of BCG bacilli in urothelial cells, to
cytokine- and chemokine-mediated recruitment of neutrophils, monocytes,
macrophages, T cells, B cells and natural killer cells. In addition, we describe
the process of trained immunity, the non-specific protective effects of BCG.
Recent studies also indicate that dysbiosis of the urinary microbiome may cause
lower urinary tract dysfunction. Side effects of BCG bladder instillations range
from common, mild and transient symptoms, such as dysuria and flu-like symptoms,
to more severe and rarely occurring life-threatening complications. We review
the literature and give an overview of reported incidences and management of BCG
infections after intravesical instillation. PURPOSE: Programmed cell death-1 ligand-1 (PD-L1) expression has been associated
with prognostic implications in urologic maligcies. We aimed to investigate
prognostic significance of pre- and post-treatment PD-L1 expression in patients
treated with BCG for high-grade non-muscle-invasive bladder cancer (NMIBC).
METHODS: We reviewed a total of 141 high-grade NMIBC cases treated with
transurethral resection + ≥ 6 BCG instillations between 2004 and 2017. PD-L1
immunohistochemistry (IHC) scoring was done on 0-3 scale, and cut-off for
positive and high-level PD-L1 expression was set to ≥ 1% and ≥ 5% staining of
tumor-infiltrating immune cells (IC), respectively. Clinicopathologic
characteristics and oncologic outcomes [recurrence-free (RFS) and
progression-free survival (PFS)] were compared, stratified by PD-L1 positivity.
The prognostic role of PD-L1 was assessed using Kaplan-Meier, and univariate and
multivariate Cox regression analyses.
RESULTS: Pre-treatment, 46.2% and 6.8% of high-grade NMIBC demonstrated positive
and high-level PD-L1 expression, respectively. Positive PD-L1 expression was
associated with submucosal invasion and refractory-tumor recurrence. PD-L1
expression was not associated with RFS or PFS in regression analysis.
Post-treatment, 55.1% and 11.6% of recurrent tumors demonstrated positive and
high-level PD-L1 expression, respectively. Down-regulation of PD-L1 expression
was noted in patients with refractory recurrence (p = 0.012).
CONCLUSION: Pre-treatment PD-L1 expression was associated with unfavorable
pathological features in primary high-grade NMIBC and its expression level after
BCG immunotherapy was significantly decreased in patients with refractory
recurrence. PD-L1 expression did not have prognostic value for PFS or RFS;
therefore, further research is necessary to identify novel biomarkers for
prediction of disease outcomes in high-grade NMIBC. INTRODUCTION: Non-muscle-invasive bladder cancer (NMIBC) is usually effectively
treated with transurethral resection (TUR), most often followed by intravesical
instillation of bacillus Calmette-Guérin (BCG) or intravesical chemotherapy.
Although the precise mechanism of BCG immunotherapy is still unclear, a local
immune response is presumed. However, a number of severe side effects and
complications are related to intravesical immunotherapy.
AIM: Aim of this report is to present rare case of the renal granulomatous
disease in a patient previously treated with intravesical instillation of BCG
immunotherapy, following TURBT. In addition, we performed review of previously
reported cases of renal granulomas following intravesical BCG immunotherapy.
CASE REPORT: A 79-year-old man was presented to Urology Clinic due to clinically
verified tumor of the urinary bladder. After transurethral resection of bladder
tumor, histopathological analysis revealed the diagnosis of papillary urothelial
high-grade pT1 carcinoma. Intravesical BCG immunotherapy was initiated,
according to protocol currently used in our institution. Upon completion of
therapy with BCG, we re-examined the patient and, using ultrasound, found a
change in the right kidney, resembling moth bites not seen on CT scan before
TURBT. Additionally, CT-guided core-needle biopsy of the affected kidney was
performed, and the specimen was sent for histopathological analysis, which
revealed chronic necrotizing granulomatous inflammation. Antituberculotic
therapy was initiated for 6 months. Upon completion of antituberculotic therapy,
control CT-scan was performed at follow-up, indicating regression of changes on
the right kidney.
CONCLUSION: This case report emphasizes the importance of consistent
implementation of follow-up protocol and the identification of lesions during
the asymptomatic period and enables the proper treatment of the disease. To
reduce the incidence of adverse effects of BCG treatment for bladder tumors, an
individualized approach is needed. |
Which epigenetic marks are deposited by PRC1? | PRC2 induces histone H3 lysine 27 (H3K27) trimethylation (H3K27me3), which is subsequently read by PRC1 that further catalyzes H2A monoubiquitination (H2Aub1), creating a transcriptional silent chromatin conformation. | BACKGROUND: The INK4/ARF locus encodes three tumor suppressor genes (p15(Ink4b),
Arf and p16(Ink4a)) and is frequently inactivated in a large number of human
cancers. Mechanisms regulating INK4/ARF expression are not fully characterized.
PRINCIPAL FINDINGS: Here we show that in young proliferating embryonic
fibroblasts (MEFs) the Polycomb Repressive Complex 2 (PRC2) member EZH2 together
with PRC1 members BMI1 and M33 are strongly expressed and localized at the
INK4/ARF regulatory domain (RD) identified as a DNA replication origin. When
cells enter senescence the binding to RD of both PRC1 and PRC2 complexes is lost
leading to a decreased level of histone H3K27 trimethylation (H3K27me3). This
loss is accompanied with an increased expression of the histone demethylase
Jmjd3 and with the recruitment of the MLL1 protein, and correlates with the
expression of the Ink4a/Arf genes. Moreover, we show that the Polycomb protein
BMI1 interacts with CDC6, an essential regulator of DNA replication in
eukaryotic cells. Finally, we demonstrate that Polycomb proteins and associated
epigenetic marks are crucial for the control of the replication timing of the
INK4a/ARF locus during senescence.
CONCLUSIONS: We identified the replication licencing factor CDC6 as a new
partner of the Polycomb group member BMI1. Our results suggest that in young
cells Polycomb proteins are recruited to the INK4/ARF locus through CDC6 and the
resulting silent locus is replicated during late S-phase. Upon senescence, Jmjd3
is overexpressed and the MLL1 protein is recruited to the locus provoking the
dissociation of Polycomb from the INK4/ARF locus, its transcriptional activation
and its replication during early S-phase. Together, these results provide a
unified model that integrates replication, transcription and epigenetics at the
INK4/ARF locus. We have recently reported that the protein ZRF1 specifically binds to
monoubiquitinated histone H2A and derepresses Polycomb target genes at the onset
of cellular differentiation. Our results suggest that ZRF1 exerts its function
in a two-step mechanism, by initially displacing the Polycomb-repressive complex
1 (PRC1) from chromatin and subsequently acting together with histone
H2A-specific deubiquitinases to facilitate transcriptional activation of its
target genes. These findings demonstrate an ambiguity of the epigenetic
monoubiquitin mark at histone H2A. Once considered to be a hallmark of gene
silencing, it is now clear that this mark can also be utilized as a recruitment
platform for proteins engaged in gene activation. Genome-wide analyses
demonstrate that ZRF1 is recruited to typical Polycomb target genes, thereby
putting it in a position to have an impact on differentiation and animal
development. This molecular mechanism for ZRF1 may represent one of the first
steps in switching silenced genes to a transcriptionally active state. We
discuss here our recent findings in the light of progress made in understanding
Polycomb-mediated silencing. The correlation between DNA methylation and a subset of histone
post-translational modifications (positive and negative) has hinted at an
underlying regulatory crosstalk between histone marks and DNA methylation in
patterning the human DNA methylome, an idea further supported by corresponding
alterations to both histone marks and DNA methylation during maligt
transformation. This study investigated the framework by which histone marks
influence DNA methylation at a genome-wide level. Using RNAi in a pluripotent
human embryonic carcinoma cell line we depleted essential components of the
MLL/COMPASS, polycomb repressive complex 2 (PRC2), and PRC1 histone modifying
complexes that establish, respectively, the post-translational modifications
H3K4me3, H3K27me3, and H2AK119ub, and assayed the impact of the subsequent
depletion of these marks on the DNA methylome. Absence of H2AK119ub resulted
predomitly in hypomethylation across the genome. Depletion of H3K4me3 and,
surprisingly, H3K27me3 caused CpG island hypermethylation at a subset of loci.
Intriguingly, many promoters were co-regulated by all three histone marks,
becoming hypermethylated with loss of H3K4me3 or H3K27me3 and hypomethylated
with depletion of H2AK119ub, and many of these co-regulated loci were among
those commonly targeted for aberrant hypermethylation in cancer. Taken together,
our results elucidate novel roles for polycomb and MLL/COMPASS in regulating DNA
methylation and define targets of this regulation. Polycomb group (PcG) proteins constitute a major epigenetic mechanism for gene
repression throughout the plant life. For a long time, the PcG mechanism has
been proposed to follow a hierarchical recruitment of PcG repressive complexes
(PRCs) to target genes in which the binding of PRC2 and the incorporation of H3
lysine 27 trimethyl marks led to recruitment of PRC1, which in turn mediated H2A
monoubiquitination. However, recent studies have turned this model upside-down
by showing that PRC1 activity can be required for PRC2 recruitment and H3K27me3
marking. Here, we review the current knowledge on plant PRC1 composition and
mechanisms of repression, as well as its role during plant development. Polycomb repressive complex 1 (PRC1) is required for ubiquitination of histone
H2A lysine 119, an epigenetic mark associated with repression of genes important
in developmental regulation. The E3 ligase activity of PRC1 resides in the
RING1A/B subunit when paired with one of six PCGF partners. The best known of
these is the oncogene BMI1/PCGF4. We find that canonical PRC1 E3 ligases such as
PCGF4-RING1B have intrinsically very low enzymatic activity compared with
non-canonical PRC1 RING dimers. The structure of a high-activity variant in
complex with E2 (PCGF5-RING1B-UbcH5c) reveals only subtle differences from an
earlier PCGF4 complex structure. However, two charged residues present in the
modelled interface with E2-conjugated ubiquitin prove critical: in BMI1/PCGF4,
these residues form a salt bridge that may limit efficient ubiquitin transfer.
The intrinsically low activity of the PCGF4-RING1B heterodimer is offset by a
relatively favourable interaction with nucleosome substrates, resulting in an
efficient site-specific monoubiquitination. Centromeres are characterized by the centromere-specific H3 variant CENP-A,
which is embedded in chromatin with a pattern characteristic of active
transcription that is required for centromere identity. It is unclear how
centromeres remain transcriptionally active despite being flanked by repressive
pericentric heterochromatin. To further understand centrochromatin's response to
repressive signals, we nucleated a Polycomb-like chromatin state within the
centromere of a human artificial chromosome (HAC) by tethering the
methyltransferase EZH2. This led to deposition of the H3K27me3 mark and PRC1
repressor binding. Surprisingly, this state did not abolish HAC centromere
function or transcription, and this apparent resistance was not observed on a
noncentromeric locus, where transcription was silenced. Directly tethering the
reader/repressor PRC1 bypassed this resistance, inactivating the centromere. We
observed analogous responses when tethering the heterochromatin Editor
Suv39h1-methyltransferase domain (centromere resistance) or reader HP1α
(centromere inactivation), respectively. Our results reveal that the HAC
centromere can resist repressive pathways driven by H3K9me3/H3K27me3 and may
help to explain how centromeres are able to resist inactivation by flanking
heterochromatin. Precise expression patterns of genes in time and space are essential for proper
development of multicellular organisms. Dynamic chromatin conformation and
spatial organization of the genome constitute a major step in this regulation to
modulate developmental outputs. Polycomb repressive complexes (PRCs) mediate
stable or flexible gene repression in response to internal and environmental
cues. In Arabidopsis thaliana, LHP1 co-localizes with H3K27me3 epigenetic marks
throughout the genome and interacts with PRC1 and PRC2 members as well as with a
long noncoding RNA. Here, we show that LHP1 is responsible for the spreading of
H3K27me3 towards the 3' end of the gene body. We also identified a subset of
LHP1-activated genes and demonstrated that LHP1 shapes local chromatin topology
in order to control transcriptional co-regulation. Our work reveals a general
role of LHP1 from local to higher conformation levels of chromatin configuration
to determine its accessibility to define gene expression patterns. |
Does erenumab target the calcitonin gene-related peptide? | No, erenumab targets the calcitonin gene-related peptide receptor. | |
Which key gene is involved in interstitial 6q25 microdeletion syndrome? | Interstitial deletions of the long arm of chromosome 6 are rare. Clinically, these deletions are considered to be part of a unique microdeletion syndrome associated with intellectual disability and speech impairment, typical dysmorphic features, structural anomalies of the brain, microcephaly, and non-specific multiple organ anomalies. ARID1B is the key gene behind 6q microdeletion syndrome. | Interstitial deletions of the long arm of chromosome 6 are rare. Clinically,
these deletions are considered to be part of a unique microdeletion syndrome
associated with intellectual disability and speech impairment, typical
dysmorphic features, structural anomalies of the brain, microcephaly, and
non-specific multiple organ anomalies. The critical region for the interstitial
6q microdeletion phenotype was mapped to 6q24-6q25, particularly the 6q25.3
region containing the genes ARID1B and ZDHHC14. It has been hypothesized that
haploinsufficiency of these genes impairs normal development of the brain and is
responsible for the phenotype. This case report describes a girl presenting with
typical features of 6q microdeletion syndrome, including global developmental
delay, speech impairment, distinct dysmorphic features, dysgenesis of the corpus
callosum, common limb anomalies, and hearing loss. Chromosome analysis by
array-CGH revealed a small interstitial 6q deletion spanning approximately 1.1
Mb of DNA and containing only one coding gene, ARID1B. We suggest that ARID1B is
the key gene behind 6q microdeletion syndrome, and we discuss its possible role
in the phenotypic manifestations. |
Brensocatib was tested for treatment of which disease? | Brensocatib was tested for bronchiectasis. Brensocatib in patients with bronchiectasis was associated with improvements in bronchiectasis clinical outcomes. | |
What is the function of the protein Cuf1? | Cuf1 is a copper-sensing transcription factor. | Copper is an essential nutrient that serves as a co-factor for enzymes involved
in critical cellular processes including energy generation, peptide hormone
maturation, oxidative stress protection, and iron homeostasis. Although genes
have been identified from yeast and mammals encoding a homologous subunit of a
plasma membrane high affinity copper transporter, the presence of additional
subunits that function as part of a copper transport complex has not been
reported. We observed that ctr4(+), a previously identified copper transport
protein from the fission yeast Schizosaccharomyces pombe, fails to complement
bakers' yeast cells defective in high affinity copper transport and fails to be
targeted to the plasma membrane. However, selection for S. pombe genes, which,
when co-expressed with Ctr4, confer high affinity copper transport to S.
cerevisiae cells resulted in the identification of ctr5(+). Both Ctr4 and Ctr5
are integral membrane proteins, are co-regulated by copper levels and the
copper-sensing transcription factor Cuf1, physically associate in vivo, are
interdependent for secretion to the plasma membrane, and are each essential for
high affinity copper transport. These studies in S. pombe identify Ctr4 and Ctr5
as components of a novel eukaryotic heteromeric plasma membrane complex that is
essential for high affinity copper transport. Aerobic organisms possess efficient systems for the transport of copper. This
involves transporters that mediate the passage of copper across biological
membranes to reach essential intracellular copper-requiring enzymes. In this
report, we identify a new copper transporter in Schizosaccharomyces pombe,
encoded by the ctr6(+) gene. The transcription of ctr6(+) is induced under
copper-limiting conditions. This regulation is mediated by the cis-acting
promoter element CuSE (copper-signaling element) through the copper-sensing
transcription factor Cuf1. An S. pombe strain bearing a disrupted ctr6Delta
allele displays a strong reduction of copper,zinc superoxide dismutase activity.
When the ctr6+ gene is overexpressed from the thiamine-inducible nmt1(+)
promoter, the cells are unable to grow on medium containing exogenous copper.
Surprisingly, this copper-sensitive growth phenotype is not due to an increase
of copper uptake at the cell surface. Instead, copper delivery across the plasma
membrane is reduced. Consistently, this results in repressing ctr4(+) gene
expression. By using a functional ctr6(+) epitope-tagged allele expressed under
the control of its own promoter, we localize the Ctr6 protein on the membrane of
vacuoles. Furthermore, we demonstrate that Ctr6 is an integral membrane protein
that can trimerize. Moreover, we show that Ctr6 harbors a putative
copper-binding Met-X-His-Cys-X-Met-X-Met motif in the amino terminus, which is
essential for its function. Our findings suggest that under conditions in which
copper is scarce, Ctr6 is required as a means to mobilize stored copper from the
vacuole to the cytosol. In this study, we examine the fate of the nuclear pool of the
Schizosaccharomyces pombe transcription factor Cuf1 in response to variations in
copper levels. A nuclear pool of Cuf1-green fluorescent protein (GFP) was
generated by expressing a functional cuf1(+)-GFP allele in the presence of a
copper chelator. We then extinguished cuf1(+)-GFP expression and tracked the
changes in the localization of the nuclear pool of Cuf1-GFP in the presence of
low or high copper concentrations. Treating cells with copper as well as silver
ions resulted in the nuclear export of Cuf1. We identified a leucine-rich
nuclear export signal (NES), (349)LAALNHISAL(358), within the C-terminal region
of Cuf1. Mutations in this sequence abrogated Cuf1 export from the nucleus.
Furthermore, amino acid substitutions that impair Cuf1 NES function resulted in
increased target gene expression and a concomitant cellular hypersensitivity to
copper. Export of the wild-type Cuf1 protein was inhibited by leptomycin B
(LMB), a specific inhibitor of the nuclear export protein Crm1. We further show
that cells expressing a temperature-sensitive mutation in crm1(+) exhibit
increased nuclear accumulation of Cuf1 at the nonpermissive temperature.
Although wild-type Cuf1 is localized in the nucleus in both conditions, we
observed that the protein can still be inactivated by copper, resulting in the
repression of ctr4(+) gene expression in the presence of exogenous copper. These
results demonstrate that nuclear accumulation of Cuf1 per se is not sufficient
to cause the unregulated expression of the copper transport genes like ctr4(+).
In addition to nuclear localization, a functional Cys-rich domain or NES element
in Cuf1 is required to appropriately regulate copper transport gene expression
in response to changes in intracellular copper concentration. |
How many groups of viruses exist in the Baltimore Classification? | There are seven "Baltimore classes" (BCs) that define the major features of virus reproduction. | The innate immune system of humans and other mammals responds to
pathogen-associated molecular patterns (PAMPs) that are conserved across broad
classes of infectious agents such as bacteria and viruses. We hypothesized that
a blood-based transcriptional signature could be discovered indicating a host
systemic response to viral infection. Previous work identified host
transcriptional signatures to individual viruses including influenza,
respiratory syncytial virus and dengue, but the generality of these signatures
across all viral infection types has not been established. Based on 44 publicly
available datasets and two clinical studies of our own design, we discovered and
validated a four-gene expression signature in whole blood, indicative of a
general host systemic response to many types of viral infection. The signature's
genes are: Interferon Stimulated Gene 15 (ISG15), Interleukin 16 (IL16),
2',5'-Oligoadenylate Synthetase Like (OASL), and Adhesion G Protein Coupled
Receptor E5 (ADGRE5). In each of 13 validation datasets encompassing human,
macaque, chimpanzee, pig, mouse, rat and all seven Baltimore virus
classification groups, the signature provides statistically significant
(p < 0.05) discrimination between viral and non-viral conditions. The signature
may have clinical utility for differentiating host systemic inflammation (SI)
due to viral versus bacterial or non-infectious causes. Viruses and mobile genetic elements are molecular parasites or symbionts that
coevolve with nearly all forms of cellular life. The route of virus replication
and protein expression is determined by the viral genome type. Comparison of
these routes led to the classification of viruses into seven "Baltimore classes"
(BCs) that define the major features of virus reproduction. However, recent
phylogenomic studies identified multiple evolutionary connections among viruses
within each of the BCs as well as between different classes. Due to the modular
organization of virus genomes, these relationships defy simple representation as
lines of descent but rather form complex networks. Phylogenetic analyses of
virus hallmark genes combined with analyses of gene-sharing networks show that
replication modules of five BCs (three classes of RNA viruses and two classes of
reverse-transcribing viruses) evolved from a common ancestor that encoded an
RNA-directed RNA polymerase or a reverse transcriptase. Bona fide viruses
evolved from this ancestor on multiple, independent occasions via the
recruitment of distinct cellular proteins as capsid subunits and other
structural components of virions. The single-stranded DNA (ssDNA) viruses are a
polyphyletic class, with different groups evolving by recombination between
rolling-circle-replicating plasmids, which contributed the replication protein,
and positive-sense RNA viruses, which contributed the capsid protein. The
double-stranded DNA (dsDNA) viruses are distributed among several large
monophyletic groups and arose via the combination of distinct structural modules
with equally diverse replication modules. Phylogenomic analyses reveal the finer
structure of evolutionary connections among RNA viruses and reverse-transcribing
viruses, ssDNA viruses, and large subsets of dsDNA viruses. Taken together,
these analyses allow us to outline the global organization of the virus world.
Here, we describe the key aspects of this organization and propose a
comprehensive hierarchical taxonomy of viruses. |
What is the effect of Dkk1 in Wnt signaling? | Transcriptional silencing of the Wnt-antagonist DKK1 is a secreted protein that antagonizes Wnt signaling and plays essential roles in vertebrate embryogenesis. | mRNA injection into the ventral blastomeres of Xenopus embryos of mRNA encoding
Wnt pathway genes induces a secondary axis with complete head structures. To
identify target genes of the pre-MBT dorsalization pathway that might be
responsible for head formation in zebrafish, we have cloned zebrafish dickkopf1
(dkk1), which is expressed in tissues implicated in head patterning. We found
that dkk1 blocks the post-MBT Wnt signaling and dkk1 is a target of the pre-MBT
Wnt signaling. Dkk1 overexpression in the prechordal plate suggests that Dkk1,
secreted from the prechordal plate, expands the forebrain at the expense of the
midbrain in the anterior neural plate. Furthermore, dkk1 acts in parallel to the
homeobox gene bozozok and bozozok is required for the maintece of dkk1
expression. The nodal gene squint is also required for the maintece of dkk1
expression. Among the mutually dependent target genes of the pre-MBT Wnt
signaling, dkk1 plays an important role in patterning the anterior head of
zebrafish. BACKGROUND: Myeloma cells may secrete factors that affect the function of
osteoblasts, osteoclasts, or both.
METHODS: We subjected purified plasma cells from the bone marrow of patients
with newly diagnosed multiple myeloma and control subjects to oligonucleotide
microarray profiling and biochemical and immunohistochemical analyses to
identify molecular determits of osteolytic lesions.
RESULTS: We studied 45 control subjects, 36 patients with multiple myeloma in
whom focal lesions of bone could not be detected by magnetic resoce imaging
(MRI), and 137 patients in whom MRI detected such lesions. Different patterns of
expression of 57 of approximately 10,000 genes from purified myeloma cells could
be used to distinguish the two groups of patients (P<0.001). Permutation
analysis, which adjusts the significance level to account for multiple
comparisons in the data sets, showed that 4 of these 57 genes were significantly
overexpressed by plasma cells from patients with focal lesions. One of these
genes, dickkopf 1 (DKK1), and its corresponding protein (DKK1) were studied in
detail because DKK1 is a secreted factor that has been linked to the function of
osteoblasts. Immunohistochemical analysis of bone marrow-biopsy specimens showed
that only myeloma cells contained detectable DKK1. Elevated DKK1 levels in bone
marrow plasma and peripheral blood from patients with multiple myeloma
correlated with the gene-expression patterns of DKK1 and were associated with
the presence of focal bone lesions. Recombit human DKK1 or bone marrow serum
containing an elevated level of DKK1 inhibited the differentiation of osteoblast
precursor cells in vitro.
CONCLUSIONS: The production of DKK1, an inhibitor of osteoblast differentiation,
by myeloma cells is associated with the presence of lytic bone lesions in
patients with multiple myeloma. Whereas the adult gastrointestinal epithelium undergoes tremendous self-renewal
through active proliferation in crypt stem cell compartments, the responsible
growth factors regulating this continuous proliferation have not been defined.
The exploration of physiologic functions of Wnt proteins in adult organisms has
been hampered by functional redundancy and the necessity for conditional
inactivation strategies. Dickkopf-1 (Dkk1) is a potent secreted Wnt antagonist
that interacts with Wnt coreceptors of the LRP family. To address the
contribution of Wnt signaling to gastrointestinal epithelial proliferation,
adenoviral expression of Dkk1 was used to achieve stringent, conditional, and
reversible Wnt inhibition in adult animals. Adenovirus Dkk1 (Ad Dkk1) treatment
of adult mice repressed expression of the Wnt target genes CD44 and EphB2 within
2 days in both small intestine and colon, indicating an extremely broad role for
Wnt signaling in the maintece of adult gastrointestinal gene expression. In
parallel, Ad Dkk1 markedly inhibited proliferation in small intestine and colon,
accompanied by progressive architectural degeneration with the loss of crypts,
villi, and glandular structure by 7 days. Whereas decreased Dkk1 expression at
later time points (>10 days) was followed by crypt and villus regeneration,
which was consistent with a reversible process, substantial mortality ensued
from colitis and systemic infection. These results indicate the efficacy of
systemic expression of secreted Wnt antagonists as a general strategy for
conditional inactivation of Wnt signaling in adult organisms and illustrate a
striking reliance on a single growth factor pathway for the maintece of the
architecture of the adult small intestine and colon. Wnt signaling plays an important role in embryonic development and
tumorigenesis. These biological effects are exerted by activation of the
beta-catenin/TCF transcription complex and consequent regulation of a set of
downstream genes. TCF-binding elements have been found in the promoter regions
of many TCF target genes and characterized by a highly conserved consensus
sequence. Utilizing this consensus sequence, we performed an in silico screening
for new TCF target genes. Through computational screening and subsequent
experimental analysis, we identified a novel TCF target gene, DKK1, which has
been shown to be a potent inhibitor of Wnt signaling. Our finding suggests the
existence of a novel feedback loop in Wnt signaling. DKK1 is a secreted protein that antagonizes Wnt signaling and plays essential
roles in vertebrate embryogenesis including head induction, skeletal
development, and limb patterning. DKK1 is also implicated in osteoporosis,
arthritis, and cancer and represents a potential therapeutic target for the
treatment of these diseases. DKK1 is a high affinity antagonistic ligand for
LRP6, which is a Wnt coreceptor that acts together with the Frizzled serpentine
receptor to initiate Wnt signal transduction. Two different models have been
proposed to account for the mechanism by which DKK1 antagonizes LRP6 function.
One model suggests that DKK1 binding to LRP6 disrupts Wnt-induced Frizzled-LRP6
complex formation, whereas the other model proposes that DKK1 interaction with
LRP6 promotes LRP6 internalization and degradation, thereby reducing the cell
surface LRP6 level. To clarify the molecular basis of DKK1 action, we examined
how DKK1 affects the endogenous LRP6 in several mammalian cell lines including
mouse embryonic fibroblasts. Here we show that DKK1 inhibits Wnt signaling but
induces neither LRP6 down-regulation from the cell surface nor reduction of
total LRP6 protein level and that DKK1 has no effect on the rate of continuous
internalization of LRP6 and the half-life (about 4.7 h) of LRP6. We conclude
that DKK1 inhibition of LRP6 is independent of LRP6 internalization and
degradation. Parathyroid hormone (PTH) suppresses Dickkopf 1 (Dkk1) expression in
osteoblasts. To determine whether this suppression is essential for PTH-mediated
Wnt signaling and bone formation, we examined mice that overexpress Dkk1 in
osteoblasts (Dkk1 mice). Dkk1 mice were osteopenic due to abnormal osteoblast
and osteoclast activity. When fed a low-calcium diet, and in two other models of
hyperparathyroidism, these mice failed to develop the peritrabecular stromal
cell response ("osteitis fibrosis") and new bone formation seen in wild-type
mice. Despite these effects of Dkk1 overexpression, PTH still activated Wnt
signaling in Dkk1 mice and in osteoblastic cells cultured from these mice. In
cultured MC3T3E1 preosteoblastic cells, PTH dramatically suppressed Dkk1
expression, induced PKA-mediated phosphorylation of beta-catenin, and
significantly enhanced Lef1 expression. Our findings indicate that the full
actions of PTH require intact Wnt signaling but that PTH can activate the Wnt
pathway despite overexpression of Dkk1. PURPOSE: Wnt signaling was demonstrated to be activated in chronic lymphocytic
leukemia (CLL). It is thought to be responsible for the extended survival of CLL
cells in vivo. Dickkopf1 (DKK1) is known to antagonize Wnt signaling by direct
high-affinity binding to the extracellular domain of WNT coreceptor lipoprotein
receptor-related protein 6 (LRP6). The purpose of this study was to investigate
the effect of DKK1 in B-CLL cells in vitro.
METHODS: Expression of DKK1 was estimated by Western blot and real-time PCR. B
cells from patients with CLL and healthy donors were incubated with recombit
DKK1. Survival was measured by flow cytometry. Primers for real-time PCR were
designed for extracellular domain of LRP6, responsible for DKK1 binding, and the
intracellular region, essential for inhibiting GSK3 β.
RESULTS: Healthy and CLL cells express equivalent mRNA levels of DKK1 and LRP6.
After treatment of CLL cells with recombit DKK1 (1 μg/mL) for 3 h, there was
no change in the levels of phosphorylated β-catenin and total β-catenin. Healthy
B cells proved to have significantly higher levels of extracellular, DKK1
binding domain of LRP6. We estimated that in CLL cells every 6th LRP6 receptor
is lacking the extracellular domain.
DISCUSSION: For the first time we show the expression of DKK1 in CLL cells.
Unlike in similar tumors, the addition of DKK1 to culture of CLL cells does not
inactivate WNT pathway. The reason for this could be the absence of the binding
domain of LRP6. On the other hand, a truncated LRP6 without extracellular DKK1
binding domain could lead to an uncontrollable activation of WNT signaling. Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal disease characterized
by late diagnosis and treatment resistance. Recurrent genetic alterations in
defined genes in association with perturbations of developmental cell signaling
pathways have been associated with PDAC development and progression. Here, we
show that GATA6 contributes to pancreatic carcinogenesis during the temporal
progression of pancreatic intraepithelial neoplasia by virtue of Wnt pathway
activation. GATA6 is recurrently amplified by both quantitative-PCR and
fluorescent in-situ hybridization in human pancreatic intraepithelial neoplasia
and in PDAC tissues, and GATA6 copy number is significantly correlated with
overall patient survival. Forced overexpression of GATA6 in cancer cell lines
enhanced cell proliferation and colony formation in soft agar in vitro and
growth in vivo, as well as increased Wnt signaling. By contrast siRNA mediated
knockdown of GATA6 led to corresponding decreases in these same parameters. The
effects of GATA6 were found to be due to its ability to bind DNA, as forced
overexpression of a DNA-binding mutant of GATA6 had no effects on cell growth in
vitro or in vivo, nor did they affect Wnt signaling levels in these same cells.
A microarray analysis revealed the Wnt antagonist Dickopf-1 (DKK1) as a
dysregulated gene in association with GATA6 knockdown, and direct binding of
GATA6 to the DKK1 promoter was confirmed by chromatin immunoprecipitation and
electrophoretic mobility shift assays. Transient transfection of GATA6, but not
mutant GATA6, into cancer cell lines led to decreased DKK1 mRNA expression and
secretion of DKK1 protein into culture media. Forced overexpression of DKK1
antagonized the effects of GATA6 on Wnt signaling in pancreatic cancer cells.
These findings illustrate that one mechanism by which GATA6 promotes pancreatic
carcinogenesis is by virtue of its activation of canonical Wnt signaling via
regulation of DKK1. The Wnt/β-catenin pathway plays a crucial role in the pathogenesis of various
human cancers. In multiple myeloma (MM), aberrant auto-and/or paracrine
activation of canonical Wnt signaling promotes proliferation and dissemination,
while overexpression of the Wnt inhibitor Dickkopf1 (DKK1) by MM cells
contributes to osteolytic bone disease by inhibiting osteoblast differentiation.
Since DKK1 itself is a target of TCF/β-catenin mediated transcription, these
findings suggest that DKK1 is part of a negative feedback loop in MM and may act
as a tumor suppressor. In line with this hypothesis, we show here that DKK1
expression is low or undetectable in a subset of patients with advanced MM as
well as in MM cell lines. This absence of DKK1 is correlated with enhanced Wnt
pathway activation, evidenced by nuclear accumulation of β-catenin, which in
turn can be antagonized by restoring DKK1 expression. Analysis of the DKK1
promoter revealed CpG island methylation in several MM cell lines as well as in
MM cells from patients with advanced MM. Moreover, demethylation of the DKK1
promoter restores DKK1 expression, which results in inhibition of
β-catenin/TCF-mediated gene transcription in MM lines. Taken together, our data
identify aberrant methylation of the DKK1 promoter as a cause of DKK1 silencing
in advanced stage MM, which may play an important role in the progression of MM
by unleashing Wnt signaling. 17β-estradiol (E2 or estrogen) is an endogenous steroid hormone that is well
known to exert neuroprotection. Along these lines, one mechanism through which
E2 protects the hippocampus from cerebral ischemia is by preventing the
post-ischemic elevation of Dkk1, a neurodegenerative factor that serves as an
antagonist of the canonical Wnt signaling pathway, and simultaneously inducing
pro-survival Wnt/β-Catenin signaling in hippocampal neurons. Intriguingly, while
expression of Dkk1 is required for proper neural development, overexpression of
Dkk1 is characteristic of many neurodegenerative diseases, such as stroke,
Alzheimer's disease, Parkinson's disease, and temporal lobe epilepsy. In this
review, we will briefly summarize the canonical Wnt signaling pathway, highlight
the current literature linking alterations of Dkk1 and Wnt/β-Catenin signaling
with neurological disease, and discuss E2's role in maintaining the delicate
balance of Dkk1 and Wnt/β-Catenin signaling in the adult brain. Finally, we will
consider the implications of long-term E2 deprivation and hormone therapy on
this crucial neural pathway. This article is part of a Special Issue entitled
Hormone Therapy. Development of the anterior forebrain precursor (AFBP) in the anterior neural
plate (ANP) depends on the activation of the Hesx1 transcription factor gene.
The Hesx1-expression domain of the ANP is underlain by Dkk1-expressing tissues,
initially proximal-most anterior visceral endoderm (AVE), and later anterior
mesendoderm (AME). As Dkk1-null embryos fail to develop the Hesx1-expressing
domain, it is likely that Wnt signal inhibition in the ANP is required for the
Hesx1 activation. To investigate the regulation of the AFBP development, we took
advantage of epiblast stem cells (EpiSCs), which develop into the ANP in the
absence of activin signaling. Expression of Hesx1 and Six3, both involved in the
AFBP development, was strongly activated 2 days after activin removal and
concomitant addition of Wnt signal inhibitors, Dkk1 or XAV939. Furthermore, we
showed that activation of the 720-bp Hesx1 5' enhancer is responsible for Hesx1
expression in the AFBP and depends on Wnt signal inhibition. In addition, we
showed that Wnt inhibition during the first day has larger impact on the
activation of Hesx1 and Six3 than the second day, suggesting that in embryos Wnt
inhibition caused by the AVE-derived Dkk1, rather than the AME-derived Dkk1,
contributes greatly in the establishment of the AFBP. LRP6, a co-receptor for the morphogen Wnt, aids endocytosis of anthrax
complexes. Here we report that Dickkopf1 (DKK1) protein, a secreted LRP6 ligand
and antagonist, is also a modulator of anthrax toxin sensitivity. shRNA-mediated
gene silencing or TALEN-mediated gene knockout of DKK1 reduced sensitivity of
cells to PA-dependent hybrid toxins. However, unlike the solely inhibitory
effect on Wnt signaling, the effects of DKK1 overexpression on anthrax toxicity
were bidirectional, depending on its endogenous expression and cell context.
Fluorescence microscopy and biochemical analyses showed that DKK1 facilitates
internalization of anthrax toxins and their receptors, an event mediated by
DKK1-LRP6-Kremen2 complex. Monoclonal antibodies against DKK1 provided
dose-dependent protection to macrophages from killing by anthrax lethal toxin
(LT). Our discovery that DKK1 forms ternary structure with LRP6 and Kremen2 in
promoting PA-mediated toxin internalization provides a paradigm for bacterial
exploitation of mechanisms that host cells use to internalize signaling
proteins. Osteoporosis and Alzheimer's disease (AD) are the two common diseases mostly
affecting persons aged over 60. Epidemiological findings revealed that
osteoporosis and AD have a very high comorbidity. However, the mechanisms
underlying their association are poorly understood. The Wnt signaling pathway
plays a crucial role in the proper development and maintece of brain and bone
structure and function. Dickkopf-related protein 1 (Dkk1), a vital antagonist of
the Wnt signaling, was reported to be closely associated with bone homeostasis
and osteoporosis. Interestingly, high level of Dkk1 in the brain increases the
risk of AD. It is suggested that Dkk1 may be a common potent risk factor
involved in osteoporosis and AD. Therefore, we hypothesize that Dkk1 may play a
role in both osteoporosis and AD. Our hypothesis will shed new light on the
understanding of the relationship between these two diseases and help to explain
some common characters of osteoporosis and AD. Hepatocellular carcinoma (HCC) is one of the most common maligcies and
exhibits heterogeneity in terms of clinical outcomes and biological activities.
Emerging evidence has demonstrated that cancer stem cells (CSCs) play important
roles in the tumorigenesis and progression of HCC. However, the molecular
mechanisms underlying the stemness maintece of CSCs remain largely unknown.
In the present study, through real-time PCR, western blotting, luciferase
assays, RNA immunoprecipitation, and in vitro and in vivo assays, we
demonstrated that miR-217 expression was markedly increased in HCC tissues and
cells. Overexpression of miR-217 promoted, while silencing miR-217 suppressed,
the fraction of the side population and the expression of cancer stem cell
factors in vitro and tumorigenicity in vivo in HCC cells. Our findings further
demonstrated that miR-217 promoted the CSC-like phenotype via dickkopf-1 (DKK1)
targeting, resulting in constitutive activation of Wnt signaling. Moreover, the
stimulatory effects of miR-217 on stem cell properties and Wnt signaling were
antagonized by the upregulation of DKK1 in miR-217-overexpressing cells.
Conversely, the inhibitory effects of silencing miR-217 on stem cell properties
and Wnt signaling were reversed by the downregulation of DKK1 in
miR-217-downregulated cells. Therefore, our results indicate that miR-217 plays
a vital role in the CSC-like phenotypes of HCC cells and may be used as a
potential therapeutic target against HCC. Interleukin 1 beta (IL1β) and Wingless-Type MMTV Integration Site Family (WNT)
signaling are major players in Osteoarthritis (OA) pathogenesis. Despite having
a large functional overlap in OA onset and development, the mechanism of IL1β
and WNT crosstalk has remained largely unknown. In this study, we have used a
combination of computational modeling and molecular biology to reveal direct or
indirect crosstalk between these pathways. Specifically, we revealed a mechanism
by which IL1β upregulates WNT signaling via downregulating WNT antagonists, DKK1
and FRZB. In human chondrocytes, IL1β decreased the expression of Dickkopf-1
(DKK1) and Frizzled related protein (FRZB) through upregulation of nitric oxide
synthase (iNOS), thereby activating the transcription of WNT target genes. This
effect could be reversed by iNOS inhibitor 1400W, which restored DKK1 and FRZB
expression and their inhibitory effect on WNT signaling. In addition, 1400W also
inhibited both the matrix metalloproteinase (MMP) expression and
cytokine-induced apoptosis. We concluded that iNOS/NO play a pivotal role in the
inflammatory response of human OA through indirect upregulation of WNT
signaling. Blocking NO production may inhibit the loss of the articular
phenotype in OA by preventing downregulation of the expression of DKK1 and FRZB. BACKGROUND: Wnt signaling plays an essential role in tumor cell growth,
including the development of maligt mesothelioma (MM). Epigenetic silencing
of negative Wnt regulators leading to constitutive Wnt signaling has been
observed in various cancers and warrants further attention. We have reported
that a succinate ether derivative of α-tocotrienol (T3E) has potent cytotoxic
effects in MM cells. Thus, in this study, we investigated whether the anti-MM
effect of T3E could be mediated via the epigenetic alteration of the Wnt
antagonist gene, Dickkopf-1 (DKK1).
METHODS: WST-1 and cell analyzers were employed to analyze the effects of T3E on
cell viability and apoptosis of human MM cell lines (H2452, H28). Real-time PCR
and Western blot were performed to evaluate the expression at mRNA and protein
levels. Methylation status and epigenetic modifications of DKK1's promoter
regions after T3E treatment in MM cells were studied using methylation-specific
PCR and Chromatin immunoprecipitation. Small interfering RNA-mediated knockdown
-(siRNA), and specific inhibitors, were used to validate DKK1 as a target of
T3E.
RESULTS: T3E markedly impaired MM cell viability, increased the expression of
phosphorylated-JNK and DKK1 and suppressed cyclin D, a downstream target gene of
Wnt signaling. Knockdown of DKK1 expression by siRNA or a specific JNK inhibitor
confirmed the contribution of DKK1 and JNK to T3E-induced cytotoxicity in MM
cells. On the other hand, cytoskeleton-associated protein 4 (CKAP4) expression,
which promotes cell proliferation as a Wnt-independent DKK1 receptor was
inhibited by T3E. Silencing CKAP4 by -siRNA did not appear to directly affect MM
cell viability, thereby indicating that expression of both DKK1 and CKAP4 is
required. Furthermore, T3E-mediated inhibition of both DNA methyltransferases
(DNMT1, 3A, and 3B) and histone deacetylases (HDAC1, 2, 3, and 8) in MM cells
leads to increased DKK1 expression, thereby promoting tumor growth inhibition.
MM cells treated with Zebularine (a DNMT inhibitor) and sodium butyrate (an HDAC
inhibitor) exhibited cytotoxic effects, which may explain the inhibitory action
of T3E on MM cells. In addition, an enhanced expression of DKK1 in MM cells
following T3E treatment is positively correlated with the methylation status of
its promoter; T3E decreased DNA methylation and increased histone acetylation.
Moreover, T3E specifically increased histone H3 lysine 4 (H3K4) methylation
activity, whereas no effects were observed on histone H3K9 and H3K27.
CONCLUSIONS: Targeting the epigenetic induction of DKK1 may lead to effective
treatment of MM, and T3E has great potential to induce anti-MM activity. Deregulated proteolysis invariably underlies most human diseases including bone
pathologies. Metalloproteinases constitute the largest of the five protease
families, and the metzincin metalloproteinases are inhibited by the four tissue
inhibitors of metalloproteinase called TIMPs. We hypothesized that Timp genes
are essential for skeletal homeostasis. We bred individual Timp knockout mice to
generate unique mouse models, the quadruple Timp null strain (QT) as well as
mice harboring only a single Timp3 allele (QT3+/- ). QT mice are grossly smaller
and exhibit a dramatic reduction of trabeculae in long bones by μCT imaging with
a corresponding increase in metalloproteinase activity. At the cellular level,
Timp deficiency compromised differentiation markers, matrix deposition and
mineralization in neonatal osteoblasts from calvariae, as well as the
fibroblastic colony-forming unit (CFU-F) capacity of bone marrow-derived stromal
cells. In contrast, we observed that osteoclasts were overactive in the Timp
null state, consistent with the noted excessive bone resorption of QT bones.
Immunohistochemistry (IHC) and immunofluorescence (IF) analyses of bone sections
revealed higher Cathepsin K and RANKL signals upon Timp loss. Seeking the
molecular mechanism, we identified abnormal TNFα bioactivity to be a central
event in Timp-deficient mice. Specifically, TNFα triggered induction of the Wnt
signaling inhibitor Dkk1 in the osteoblasts at the mRNA and protein levels, with
a simultaneous increase in RANKL. Neutralizing TNFα antibody was capable of
rescuing the induction of Dkk1 as well as RANKL. Therefore, the generation of
novel Timp-deficient systems allowed us to uncover the essential and collective
function of TIMP proteins in mammalian long-bone homeostasis. Moreover, our
study discovers a functional TIMP/metalloproteinase-TNFα-Dkk1/RANKL nexus for
optimal control of the bone microenvironment, which dictates coexistence of the
osteoblast and osteoclast lineages. © 2018 American Society for Bone and Mineral
Research. |
What is bimagrumab | Bimagrumab is a fully human monoclonal antibody that blocks the activin type II receptors, preventing the activity of myostatin and other negative skeletal muscle regulators. | Bimagrumab (BYM338) is a novel fully human monoclonal antibody that exerts
strong promyogenic effects on skeletal muscle by blocking activin type II
receptors (ActRII). We investigated whether such blockade of ActRII by
bimagrumab manifests any detrimental effect on outcomes of bone healing in a rat
fibula osteotomy model. Animals (n = 150) were divided into 11 groups and
received weekly treatment with either bimagrumab (10 or 100 mg/kg) or vehicle.
Progression and outcomes of bone healing were assessed by lateral radiographs in
vivo as well as by peripheral quantitative computed tomography (pQCT), 4-point
bending test, and microscopic examination of the excised fibula at Day 29 or
later. The radiographic progression of bone healing showed no significant
differences between treatment groups in any comparative setting. In 3-month-old
animals, pQCT revealed slightly reduced immature callus size and bone mineral
content in bimagrumab-treated animals compared with vehicle-treated animals at
Day 29 (p < 0.05). There were, however, no differences in mature callus size,
bone mineral density, or biomechanical competency. The aforementioned effects on
immature callus size were not present when the treatment was initiated 4 weeks
post osteotomy or when treating 6-month-old animals. In summary, these findings
suggest that there is no major impact of ActRII blockade on overall fracture
healing, and delayed treatment initiation can bypass the small and transient
effect of the therapy on immature callus formation observed in younger animals.
Verification of these findings in humans is the subject of an ongoing clinical
trial on elderly hip fracture patients. BACKGROUND: Bimagrumab is a human monoclonal antibody inhibitor of activin type
II receptors (ActRII), with anabolic action on skeletal muscle mass by blocking
binding of myostatin and other negative regulators of muscle growth. Bimagrumab
is under evaluation for muscle wasting and associated functional loss in hip
fracture and sarcopenia, and in obesity. Bimagrumab also blocks other endogenous
ActRII ligands, such as activins, which act on the neurohormonal axes,
pituitary, gonads and adrenal glands.
AIM: To evaluate the effect of bimagrumab on the pituitary-gonadal and
pituitary-adrenal axes in humans.
METHODS: Healthy men and women, aged 55 to 75 years, received bimagrumab
intravenously 10 mg/kg or placebo on Day 1 and Day 29. Pituitary-gonadal and
pituitary-adrenal functions were evaluated with basal hormone measurement and
standard gonadotropin-releasing hormone (GnRH) and adrenocorticotropic hormone
(ACTH) stimulation tests at baseline, Week 8 and at the end of study (EOS)-Week
20.
RESULTS: At Week 8, follicle-stimulating hormone (FSH) levels were reduced by
42.16 IU/L (P < .001) and luteinizing hormone (LH) levels were increased by 2.5
IU/L (P = .08) over placebo in response to bimagrumab in women but not in men.
Effects that were reversible after bimagrumab was cleared. Gonadal and adrenal
androgen levels were not affected by exposure to bimagrumab.
CONCLUSION: Bimagrumab alters the function of pituitary gonadotroph cells,
consistent with blockade of activin on local ActRII. This effect is reversible
with clearance of bimagrumab. Bimagrumab did not impact gonadal and adrenal
androgen secretion. RATIONALE: Bimagrumab is a fully human monoclonal antibody that blocks the
activin type II receptors, preventing the activity of myostatin and other
negative skeletal muscle regulators.
OBJECTIVES: To assess the effects of bimagrumab on skeletal muscle mass and
function in patients with chronic obstructive pulmonary disease (COPD) and
reduced skeletal muscle mass.
METHODS: Sixty-seven patients with COPD (mean FEV1, 1.05 L [41.6% predicted];
aged 40-80 yr; body mass index < 20 kg/m2 or appendicular skeletal muscle mass
index ≤ 7.25 [men] and ≤ 5.67 [women] kg/m2), received two doses of either
bimagrumab 30 mg/kg intravenously (n = 33) or placebo (n = 34) (Weeks 0 and 8)
over 24 weeks.
MEASUREMENTS AND MAIN RESULTS: We assessed changes in thigh muscle volume (cubic
centimeters) as the primary endpoint along with 6-minute-walk distance (meters),
safety, and tolerability. Fifty-five (82.1%) patients completed the study. Thigh
muscle volume increased by Week 4 and remained increased at Week 24 in
bimagrumab-treated patients, whereas no changes were observed with placebo (Week
4: +5.9% [SD, 3.4%] vs. 0.0% [3.3%], P < 0.001; Week 8: +7.0% [3.7%] vs. -0.7%
[2.8%], P < 0.001; Week 16: +7.8% [5.1%] vs. -0.9% [4.5%], P < 0.001; Week 24:
+5.0% [4.9%] vs. -1.3% [4.3%], P < 0.001). Over 24 weeks, 6-minute-walk distance
did not increase significantly in either group. Adverse events in the bimagrumab
group included muscle-related symptoms, diarrhea, and acne, most of which were
mild in severity.
CONCLUSIONS: Blocking the action of negative muscle regulators through the
activin type II receptors with bimagrumab treatment safely increased skeletal
muscle mass but did not improve functional capacity in patients with COPD and
low muscle mass. Clinical trial registered with www.clinicaltrials.gov
(NCT01669174). |
List orally bioavailable MPS1 kinase inhibitors | 1 h-pyrrolo [3,2-c] pyridine, cct271850, nms-p715, 4-aminopyrazalo,bos172722 and cct251455. | MPS1 kinase is a key regulator of the spindle assembly checkpoint (SAC), a
mitotic mechanism specifically required for proper chromosomal alignment and
segregation. It has been found aberrantly overexpressed in a wide range of human
tumors and is necessary for tumoral cell proliferation. Here we report the
identification and characterization of NMS-P715, a selective and orally
bioavailable MPS1 small-molecule inhibitor, which selectively reduces cancer
cell proliferation, leaving normal cells almost unaffected. NMS-P715 accelerates
mitosis and affects kinetochore components localization causing massive
aneuploidy and cell death in a variety of tumoral cell lines and inhibits tumor
growth in preclinical cancer models. Inhibiting the SAC could represent a
promising new approach to selectively target cancer cells. TTK/Mps1 is a key kinase controlling progression of cell division via
participation in the mitotic spindle assembly checkpoint and is overexpressed in
a number of human cancers. Herein we report the discovery of
4-(4-aminopyrazolo[1,5-a][1,3,5]triazin-8-yl)benzamides as a potent, novel class
of TTK inhibitors. The series was identified by means of bioisosteric
replacement of the related imidazopyrazine and imidazopyridazine scaffolds.
Optimization led to the identification of compounds with excellent potency
(Ki=0.8nM) and exceptional kinase selectivity. The SAR indicates a strong
dependence of activity on the presence of the N-cyclopropyl-2-methylbenzamide
moiety delineating the geometry for 1½ type kinase inhibitor. Molecular modeling
indicates the extensive and optimal contacts, mediated through H-bonds and
hydrophobic interactions, are responsible for the selectivity and potency of the
inhibitors. The compounds demonstrate a strong anti-proliferative activity in a
panel of human cancer cell lines (HCT116 GI50<15nM) and good rodent
pharmacokinetics (oral %F 97%). BACKGROUND: The main role of the cell cycle is to enable error-free DNA
replication, chromosome segregation and cytokinesis. One of the best
characterised checkpoint pathways is the spindle assembly checkpoint, which
prevents anaphase onset until the appropriate attachment and tension across
kinetochores is achieved. MPS1 kinase activity is essential for the activation
of the spindle assembly checkpoint and has been shown to be deregulated in human
tumours with chromosomal instability and aneuploidy. Therefore, MPS1 inhibition
represents an attractive strategy to target cancers.
METHODS: To evaluate CCT271850 cellular potency, two specific antibodies that
recognise the activation sites of MPS1 were used and its antiproliferative
activity was determined in 91 human cancer cell lines. DLD1 cells with induced
GFP-MPS1 and HCT116 cells were used in in vivo studies to directly measure MPS1
inhibition and efficacy of CCT271850 treatment.
RESULTS: CCT271850 selectively and potently inhibits MPS1 kinase activity in
biochemical and cellular assays and in in vivo models. Mechanistically, tumour
cells treated with CCT271850 acquire aberrant numbers of chromosomes and the
majority of cells divide their chromosomes without proper alignment because of
abrogation of the mitotic checkpoint, leading to cell death. We demonstrated a
moderate level of efficacy of CCT271850 as a single agent in a human colorectal
carcinoma xenograft model.
CONCLUSIONS: CCT271850 is a potent, selective and orally bioavailable MPS1
kinase inhibitor. On the basis of in vivo pharmacodynamic vs efficacy
relationships, we predict that more than 80% inhibition of MPS1 activity for at
least 24 h is required to achieve tumour stasis or regression by CCT271850. Protein kinase monopolar spindle 1 plays an important role in spindle assembly
checkpoint at the onset of mitosis. Over expression of MPS1 correlated with a
wide range of human tumors makes it an attractive target for finding an
effective and specific inhibitor. In this work, we performed molecular dynamics
simulations of protein MPS1 itself as well as protein bound systems with the
inhibitor and natural substrate based on crystal structures. The reported orally
bioavailable 1 h-pyrrolo [3,2-c] pyridine inhibitors of MPS1 maintained stable
binding in the catalytic site, while natural substrate ATP could not stay.
Comparative study of stability and flexibility of three systems reveals position
shifting of β-sheet region within the catalytic site, which indicates inhibition
mechanism was through stabilizing the β-sheet region. Binding free energies
calculated with MM-GB/PBSA method shows different binding affinity for inhibitor
and ATP. Finally, interactions between protein and inhibitor during molecular
dynamic simulations were measured and counted. Residue Gly605 and Leu654 were
suggested as important hot spots for stable binding of inhibitor by molecular
dynamic simulation. Our results reveal an important position shifting within
catalytic site for non-inhibited proteins. Together with hot spots found by
molecular dynamic simulation, the results provide important information of
inhibition mechanism and will be referenced for designing novel inhibitors. |
Can radiosurgery be used for the DNET tumors? | Yes, radiosurgery is used for the DNET (Dysembryoplastic neuroepithelial) tumors. However, the level of evidence is limited. | Two rare cases of intractable epilepsy caused by Dysembryoplastic
Neuroepithelial Tumours (DNET) are reported and their different management
discussed. The first case required vagal nerve stimulation and radiosurgery
while the later was operated with the help of neuronavigation. Both had good
outcome according to Engel classification after a one year follow up. BACKGROUND: Dysembryoplastic neuroepithelial tumors (DNT/DNET) are rare
epileptogenic tumors. Microsurgery remains the best treatment option, although
case reports exist on the use of gamma knife radiosurgery (GKRS) in selected
cases. We investigated the long-term outcome of GKRS-treated DNTs at our
institution in the context of current diagnostic and treatment options.
CASE DESCRIPTIONS: We conducted a retrospective review of three consecutive
adult patients (≥18 years) treated with salvage GKRS between 2002 and 2010 at
Karolinska University Hospital, Stockholm, Sweden. The case series was
supplemented by a review of current literature. A 20-year-old male underwent
subtotal resection (STR) in 1997 and 2002 of DNT resulting in temporary control
of intractable epilepsy despite antiepileptic drug treatment (AED). Long-term
seizure control was obtained after GKRS of two separate residual DNT components
along the surgical margin (2005 and 2010). A 27-year-old male undergoing gross
total resection of the contrast-enhancing portion of a DNT (1999) resulted in
temporary control of intractable epilepsy despite AEDs; lasting clinical control
of seizures was achieved in 2002 after GKRS of a small, recurrent DNT component.
A 28-year-old male underwent STR of DNT (1994 and 2004) resulting in temporary
control of intractable epilepsy. Lasting seizure control was gained after GKRS
of a residual tumor (2005).
CONCLUSION: GKRS as performed in our series was effective in terms of tumor and
seizure control. No adverse radiation effects were recorded. Prospective studies
are warranted to establish the role of GKRS in the treatment of DNTs. |
What are commensal bacteria? | The gut microbiota is composed of a large number of microbes, usually regarded as commensal bacteria. Maintenance of the commensal bacteria that comprise the gut microbiome is essential to both gut and systemic health. | Maintece of the commensal bacteria that comprise the gut microbiome is
essential to both gut and systemic health. Traumatic injury, such as burn,
elicits a number of changes in the gut, including a shift in the composition of
the microbiome (dysbiosis), increased gut leakiness, and bacterial translocation
into the lymphatic system and bloodstream. These effects are believed to
contribute to devastating secondary complications following burn, including
pneumonia, acute respiratory distress syndrome, multi-organ failure, and septic
shock. Clinical studies demonstrate that advanced age causes a significant
increase in mortality following burn, but the role of the gut in this
age-dependent susceptibility has not been investigated. In this study, we
combined our well-established murine model of scald burn injury with bacterial
16S-rRNA gene sequencing to investigate how burn injury affects the fecal
microbiome in aged versus young mice. Of our treatment groups, the most
substantial shift in gut microbial populations was observed in aged mice that
underwent burn injury. We then profiled antimicrobial peptides (AMPs) in the
ileum, and found that burn injury stimulated a 20-fold rise in levels of
regenerating islet-derived protein 3 gamma (Reg3γ), a 16-fold rise in
regenerating islet-derived protein 3 beta (Reg3β), and an 8-fold rise in
Cathelicidin-related antimicrobial peptide (Cramp) in young, but not aged mice.
Advanced age alone elicited 5-fold higher levels of alpha defensin-related
sequence1 (Defa-rs1) in the ileum, but this increase was lost following burn.
Comparison of bacterial genera abundance and AMP expression across treatment
groups revealed distinct correlation patterns between AMPs and individual
genera. Our results reveal that burn injury drives microbiome dysbiosis and
altered AMP expression in an age-dependent fashion, and highlight potential
mechanistic targets contributing to the increased morbidity and mortality
observed in elderly burn patients. PURPOSE OF REVIEW: To summarize recent evidence regarding the presence and
potential role of the microbiome in systemic vasculitides.
RECENT FINDINGS: Microbiomic descriptions are now available in patients with
small, medium and large vessel vasculitis. The majority of studies have
evaluated gastrointestinal inhabitants, with a smaller number of studies
describing the nasal, pulmonary or vascular microbiomes. Most published studies
are observational and cross-sectional. Dysbiosis is seen frequently in
vasculitis patients with reduced microbial diversity observed in nasal, fecal
and vascular samples compared with disease and/or healthy controls. Predomit
bacteria vary, but overall, patients with vasculitis tend to have more
pathogenic and less commensal bacteria in active disease. In the few
longitudinal studies available, improvement or resolution of dysbiosis has been
observed following vasculitis treatment and improved disease activity.
SUMMARY: Dysbiosis and reduced microbial diversity has been identified in
patients with small, medium and large vessel vasculitis. Although limited data
suggests microbiomes may 'normalize' following immunosuppression, cause or
effect cannot be determined. It is hypothesized that microbial disruption in a
genetically susceptible individual may trigger excessive host immune activation
and vasculitis; however, larger studies with longitudinal and translational
design are needed to further our current understanding. |
What disease is associate with defects in both the KDM6A (lysine specific demethylase 6A) and KMT2D (lysine methyltransferase 2D) | Over the last 20 years, mutations in five key COMPASS complex genes have been linked to three human congenital syndromes: Kabuki syndrome (type 1 [KMT2D] and 2 [KDM6A] | KBG syndrome is a rare, autosomal domit disorder caused by mutations or
deletions leading to haploinsufficiency for the Ankrin Repeating
Domain-Containing protein 11 (ANKRD11) at chromosome 16q24.3. Kabuki syndrome is
caused by mutations or deletions of lysine (K)-specific methyltransferase 2D
(KMT2D) and lysine-specific methylase 6A (KDM6A). We report on a male with
developmental delays, cleft palate, craniofacial dysmorphism, hypotonia, and
central nervous system anomalies including diminished white matter with thinning
of the corpus callosum. Exome sequencing revealed a de novo mutation in ANKRD11,
c.2606_2608delAGA, predicting p.Lys869del and an additional, de novo mutation,
c.2353T>C, predicting p.Tyr785His in KDM1A, a gene not previously associated
with a human phenotype. We describe this child as the first report of a
deleterious sequence variant in KDM1A and hypothesize that his phenotype
resulted from the combined effect of both mutations. Kabuki syndrome (KS) is a rare condition with multiple congenital anomalies and
mental retardation. Exonic deletions, disrupting the lysine (K)-specific
demethylase 6A (KDM6A) gene have been demonstrated as rare cause of KS. Here, we
report a de novo 227-kb deletion in chromosome Xp11.3 of a 7-year-old Chinese
girl with KS. Besides the symptoms of KS, the patient also presented with skin
allergic manifestations, which were considered to be a new, rare feature of the
phenotypic spectrum. The deletion includes the upstream region and exons 1-2 of
KDM6A and potentially causes haploinsuffiency of the gene. We also discuss the
mutation spectrum of KDM6A and clinical variability of patients with KDM6A
deletion through a literature review. © 2016 Wiley Periodicals, Inc. Lysine methyltransferase 2D (KMT2D; OMIM 602113) encodes a histone
methyltransferase involved in transcriptional regulation of the beta-globin and
estrogen receptor as part of a large protein complex known as activating signal
cointegrator-2-containing complex (ASCOM). Heterozygous germline mutations in
the KMT2D gene are known to cause Kabuki syndrome (OMIM 147920), a developmental
multisystem disorder. Neither holoprosencephaly nor other defects in human
forebrain development have been previously associated with Kabuki syndrome. Here
we report two patients diagnosed with alobar holoprosencephaly in their
antenatal period with de novo monoallelic KMT2D variants identified by
trio-based exome sequencing. The first patient was found to have a stop-gain
variant c.12565G>T (p.Gly4189*), while the second patient had a missense variant
c.5A>G (p.Asp2Gly). Phenotyping of each patient did not reveal any age-related
feature of Kabuki syndrome. These two cases represent the first report on
association between KMT2D and holoprosencephaly. Kabuki syndrome is a rare genetic disorder, caused by mutation in the KMT2D or
KDM6A genes, which affects several organs in the majority of patients, among
which are the eyes. The most typical clinical characteristics are mental
retardation, postnatal growth retardation, skeletal anomalies, and
characteristic facial features. As the eyes are affected in most of the cases,
ophthalmological examination is recommended for the early detection of ocular
anomalies, in order to prevent visual impairment. The most frequent ocular signs
are strabismus, ptosis, and refractive anomalies. A series of cases of Kabuki
syndrome is described in five children, four of whom exhibited strabismus with
esotropia, over action of inferior oblique muscles, and under action of superior
oblique muscles associated with a V pattern. Most published papers do not report
or might underestimate the ocular problems. It may be appropriate to perform
orbital magnetic resoces in order to detect changes in the muscle paths that
are related to the pathology of the eye movements found. Kabuki syndrome (KS) is a rare disorder of transcriptional regulation with a
complex phenotype that includes cranio-facial dysmorphism, intellectual
disability, hypotonia, failure to thrive, short stature, and cardiac and renal
anomalies. Heterozygous, de novo domit mutations in either KMT2D or KDM6A
underlie KS. Limited information is available about the phenotypic spectrum of
KS in China. Fourteen Chinese patients with genetically confirmed KS were
evaluated in addition to 11 Chinese patients who were identified from the
medical literature. The clinical phenotype spectrum of these patients was
compared to that of 449 patients with KS from non-Chinese ethnicities.
Additionally, we explored the utility of a facial recognition software in
recognizing KS. All 25 patients with KS carried de novo, likely pathogenic or
pathogenic variants in either KMT2D or KDM6A. Eighteen patients were male, the
age at diagnosis ranged from 2months to 11.6 years. The facial gestalt included
arched and broad eyebrows (25/25; 100%), sparse lateral or notched eyebrows
(18/18; 100%), short columella with a concave nasal tip (24/25; 96%) and large,
prominent ears (24/24; 100%) which were more frequent in Chinese patients
(p < .01). In contrast, microcephaly (2/25; 8%), cleft lip/palate (2/25; 8%),
and cardiac defects (10/25; 40%) were less frequent in Chinese patients (not
significant). The diagnosis of KS was correctly identified in 13 of 14 patients
through facial recognition and clinical phenotyping, underscoring the utility of
this approach. As expected, there is marked phenotypic overlap between Chinese
and non-Chinese patients with KS, although subtle differences were identified. The type 2 lysine methyltransferases KMT2C and KMT2D are large, enzymatically
active scaffold proteins that form the core of nuclear regulatory structures
known as KMT2C/D COMPASS complexes (complex of proteins associating with Set1).
These evolutionarily conserved proteins regulate DNA promoter and enhancer
elements, modulating the activity of diverse cell types critical for embryonic
morphogenesis, central nervous system development, and post-natal survival.
KMT2C/D COMPASS complexes and their binding partners enhance active gene
expression of specific loci via the targeted modification of histone-3 tail
residues, in general promoting active euchromatic conformations. Over the last
20 years, mutations in five key COMPASS complex genes have been linked to three
human congenital syndromes: Kabuki syndrome (type 1 [KMT2D] and 2 [KDM6A]),
Rubinstein-Taybi syndrome (type 1 [CBP] and 2 [EP300]), and Kleefstra syndrome
type 2 (KMT2C). Here, we review the composition and biochemical function of the
KMT2 complexes. The specific cellular and embryonic roles of the KMT2C/D COMPASS
complex are highlight with a focus on clinically relevant mechanisms sensitive
to haploinsufficiency. The phenotypic similarities and differences between the
members of this new family of disorders are outlined and emerging therapeutic
strategies are detailed. Kabuki syndrome (KS) is a rare congenital disorder characterized by distinctive
facies, postnatal growth deficiency, cardiac defects and skeletal anomalies.
Studies have determined that pathogenic variants of the lysine-specific
methyltransferase 2D (KMT2D) and lysine-specific demethylase 6A (KDM6A) genes
are the major causes of KS. The two genes encode different histone-modifying
enzymes that are found in the same protein complex that is critical for cell
differentiation during development. Here we report the results from
next-generation sequencing of genomic DNA from 13 patients who had a clinical
diagnosis of KS based on facial dysmorphism and other KS-specific cardinal
phenotypes. Nine of the 13 patients were confirmed to be carrying heterozygous
pathogenic KMT2D variants, seven of which were truncating and two were missense
substitutions. Overall, we uncovered 11 novel variants - nine in KMT2D and two
in KDM6A. Seven of the novel variants (all KMT2D) were likely causative of the
KS phenotype. Our study expands the number of naturally occurring KMT2D and
KDM6A variants. The discovery of novel pathogenic variants will add to the
knowledge on disease-causing variants and the relevance of missense variants in
KS. Lysine demethylase 6A (KDM6A), also known as UTX, belongs to the KDM6 family of
histone H3 lysine 27 (H3K27) demethylases, which also includes UTY and KDM6B
(JMJD3). The KDM6A protein contains six tetratricopeptide repeat (TPR) domains
and an enzymatic Jumonji C (JmjC) domain that catalyzes the removal of di- and
trimethylation on H3K27. KDM6A physically associates with histone H3 lysine 4
monomethyltransferases MLL3 (KMT2C) and MLL4 (KMT2D). Since its identification
as an H3K27 demethylase in 2007, studies have reported KDM6A's critical roles in
cell differentiation, development, and cancer. KDM6A is important for
differentiation of embryonic stem cells and development of various tissues.
Mutations of KDM6A cause Kabuki syndrome. KDM6A is frequently mutated in cancers
and functions as a tumor suppressor. KDM6A is redundant with UTY and functions
largely independently of its demethylase activity. It regulates gene expression,
likely through the associated transcription factors and MLL3/4 on enhancers.
However, KDM6A enzymatic activity is required in certain cellular contexts.
Functional redundancy between H3K27 demethylase activities of KDM6A and KDM6B in
vivo has yet to be determined. Further understanding of KDM6A functions and
working mechanisms will provide more insights into enhancer regulation and may
help generate novel therapeutic approaches to treat KDM6A-related diseases. |
Which transcription factor regulates emergency granulopoiesis? | The transcription factor CCAAT/enhancer binding protein β (C/EBPβ) plays critical roles in the differentiation and proliferation of hematopoietic stem cells. | Severe congenital neutropenia (CN) is a heterogeneous hematopoietic syndrome
with a typical "maturation arrest" of granulocytic precursors at the
promyelocytic stage, inherited in an autosomal domit or recessive manner.
Intriguingly, CN patients have the same bone marrow and blood phenotypes
irrespective of inheritance. This suggests that mutations in various genes may
lead to the dysregulation of the common myeloid transcription factor(s) in CN.
To the extensively studied myeloid-specific transcription factors belong
CCAAT/enhancer-binding proteins (C/EBPs) (-alpha, -beta, -epsilon) and PU.1. The
relative levels of PU.1 and C/EBPalpha in granulocytic-macrophage progenitors
have been suggested to regulate monocyte versus neutrophil cell-fate choice. In
CN patients, the myelopoietic maturation program is sharply shifted toward
monocytopoiesis, with increased levels of monocytes and no granulocytes in the
peripheral blood. We found that in myeloid cells from CN patients C/EBPalpha and
its target gene inhibitor of DNA binding 1 (Id1) are abrogated due to a lack of
lymphoid enhancer-binding factor 1 (LEF-1) expression but PU.1 is slightly
upregulated. Based on these findings, we conclude that in LEF-1-deficient
myeloid cells from CN patients misbalanced C/EBPalpha/Id1:PU.1 ratio with a
strong shift toward PU.1 could play a decisive role in the improper regulation
of myelopoiesis with defective granulocytopoiesis and elevated monocytic
differentiation. Recently, we identified nicotinamide phosphoribosyltransferase
(NAMPT), also known as pre-B cell colony enhancing factor (PBEF), as an
essential enzyme mediating granulocyte colony-stimulating factor
(G-CSF)-triggered granulopoiesis in healthy individuals and in individuals with
CN. Since CN patients respond to G-CSF treatment even in the absence of LEF-1
and C/EBPalpha, we conclude that treatment of CN patients with pharmacological
doses of G-CSF activates NAMPT/NAD(+)/SIRT1-dependent "emergency" granulopoiesis
via C/EBPbeta. Granulocyte colony-stimulating factor (G-CSF) mediates "emergency"
granulopoiesis during infection, a process that is mimicked by clinical G-CSF
use, yet we understand little about the intracellular signaling cascades that
control demand-driven neutrophil production. Using a murine model with
conditional deletion of signal transducer and activator of transcription 3
(STAT3) in bone marrow, we investigated the cellular and molecular mechanisms of
STAT3 function in the emergency granulopoiesis response to G-CSF administration
or infection with Listeria monocytogenes, a pathogen that is restrained by G-CSF
signaling in vivo. Our results show that STAT3 deficiency renders hematopoietic
progenitor cells and myeloid precursors refractory to the growth-promoting
functions of G-CSF or L monocytogenes infection. STAT3 is necessary for
accelerating granulocyte cell-cycle progression and maturation in response to
G-CSF. STAT3 directly controls G-CSF-dependent expression of
CCAAT-enhancer-binding protein β (C/EBPβ), a crucial factor in the emergency
granulopoiesis response. Moreover, STAT3 and C/EBPβ coregulate c-Myc through
interactions with the c-myc promoter that control the duration of C/EBPα
occupancy during demand-driven granulopoiesis. These results place STAT3 as an
essential mediator of emergency granulopoiesis by its regulation of
transcription factors that direct G-CSF-responsive myeloid progenitor expansion. Granulopoiesis is tightly regulated to meet host demands during both
"steady-state" and "emergency" situations, such as infections. The transcription
factor CCAAT/enhancer binding protein β (C/EBPβ) plays critical roles in
emergency granulopoiesis, but the precise developmental stages in which C/EBPβ
is required are unknown. In this study, a novel flow cytometric method was
developed that successfully dissected mouse bone marrow cells undergoing
granulopoiesis into five distinct subpopulations (#1-5) according to their
levels of c-Kit and Ly-6G expression. After the induction of candidemia, rapid
mobilization of mature granulocytes and an increase in early granulocyte
precursors accompanied by cell cycle acceleration was followed by a gradual
increase in granulocytes originating from the immature populations. Upon
infection, C/EBPβ was upregulated at the protein level in all the granulopoietic
subpopulations. The rapid increase in immature subpopulations #1 and #2 observed
in C/EBPβ knockout mice at 1 d postinfection was attenuated. Candidemia-induced
cell cycle acceleration and proliferation of hematopoietic stem/progenitors were
also impaired. Taken together, these data suggest that C/EBPβ is involved in the
efficient amplification of early granulocyte precursors during
candidemia-induced emergency granulopoiesis. In contrast to the definitive role of the transcription factor, CCAAT/Enhancer
binding protein α (C/EBPα), in steady-state granulopoiesis, previous findings
have suggested that granulopoiesis during emergency situations, such as
infection, is dependent on C/EBPβ. In this study, a novel lentivirus-based
reporter system was developed to elucidate the molecular switch required for
C/EBPβ-dependency. The results demonstrated that two cyclic AMP responsive
elements (CREs) in the proximal promoter region of C/EBPβ were involved in the
positive regulation of C/EBPβ transcription during granulocyte-macrophage
colony-stimulating factor (GM-CSF)-induced differentiation of bone marrow cells.
In addition, the transcripts of CRE binding (CREB) family proteins were readily
detected in hematopoietic stem/progenitor cells. CREB was upregulated,
phosphorylated and bound to the CREs in response to GM-CSF stimulation.
Retroviral transduction of a domit negative CREB mutant reduced C/EBPβ mRNA
levels and significantly impaired the proliferation/differentiation of
granulocyte precursors, while a constitutively active form of CREB facilitated
C/EBPβ transcription. These data suggest that CREB proteins are involved in the
regulation of granulopoiesis via C/EBPβ upregulation. Cancer-driven granulo-monocytopoiesis stimulates expansion of tumor promoting
myeloid populations, mostly myeloid-derived suppressor cells (MDSCs) and
tumor-associated macrophages (TAMs). We identified subsets of MDSCs and TAMs
based on the expression of retinoic-acid-related orphan receptor (RORC1/RORγ) in
human and mouse tumor bearers. RORC1 orchestrates myelopoiesis by suppressing
negative (Socs3 and Bcl3) and promoting positive (C/EBPβ) regulators of
granulopoiesis, as well as the key transcriptional mediators of myeloid
progenitor commitment and differentiation to the monocytic/macrophage lineage
(IRF8 and PU.1). RORC1 supported tumor-promoting innate immunity by protecting
MDSCs from apoptosis, mediating TAM differentiation and M2 polarization, and
limiting tumor infiltration by mature neutrophils. Accordingly, ablation of
RORC1 in the hematopoietic compartment prevented cancer-driven myelopoiesis,
resulting in inhibition of tumor growth and metastasis. Interferon consensus sequence-binding protein (Icsbp) is required for
terminating emergency granulopoiesis, an episodic event responsible for
granulocyte production in response to infections and a key component of the
innate immune response. Icsbp inhibits the expression of Stat3 and C/ebpβ,
transcription factors essential for initiating and sustaining granulopoiesis,
and activates transcription of Fanconi C (FANCC), a DNA repair protein. In prior
studies, we noted accelerated bone marrow failure in Fancc-/- mice undergoing
multiple episodes of emergency granulopoiesis, associated with apoptosis of bone
marrow cells with unrepaired DNA damage. Additionally, we found increased
expression of Fanconi C and F proteins during emergency granulopoiesis. These
findings suggest that Icsbp protects the bone marrow from DNA damage by
increasing activity of the Fanconi DNA repair pathway, but the mechanisms for
FANCC activation during initiation of emergency granulopoiesis are unclear. In
this study, we observed that Stat3 and C/ebpβ activate FANCC transcription and
contribute to DNA repair. Our findings indicate that FancC expression is
increased during Stat3- and C/ebpβ-induced initiation of emergency
granulopoiesis by these transcription factors and is maintained through
termination by Icsbp. Our work reveals that Stat3- and C/ebpβ-mediated FancC
expression is a critical component for initiating and sustaining key innate
immune responses. Under stress conditions such as infection, inflammation, and hematopoietic
recovery following chemotherapy or transplantation, the hematopoietic system is
required to meet the increasing demands, especially from myeloid cells.
Therefore, an understanding of the molecular mechanism underlying stress
hematopoiesis is clinically imperative. We previously showed that C/EBPβ, which
is a transcription factor required for emergency granulopoiesis, plays a pivotal
role at the level of hematopoietic stem/progenitor cells under stress
conditions. Upon exposure to stress, the C/EBPβ protein is upregulated in the
hematopoietic stem cells. A close examination of C/EBPβ knockout mice revealed
that C/EBPβ regulates the proliferation and differentiation of hematopoietic
stem cells at the cost of the self-renewing activity. Further elucidation of the
functions and regulation of C/EBPβ in hematopoietic stem cells will facilitate
an understanding of stress hematopoiesis. |
When did eptinezumab get its first FDA approval? | In February 2020, eptinezumab was approved in the USA for the preventive treatment of migraine in adults. | Eptinezumab-jjmr (referred to as eptinezumab hereafter; Vyepti™) is a humanised
monoclonal antibody that binds to calcitonin gene-related peptide (CGRP) and
blocks its binding to the receptor. CGRP is believed to play a major role in the
pathophysiology of migraine. Eptinezumab, delivered by intravenous (IV)
administration, is being developed by Lundbeck Seattle BioPharmaceuticals for
the prevention of migraine. In February 2020, eptinezumab was approved in the
USA for the preventive treatment of migraine in adults. This article summarizes
the milestones in the development of eptinezumab leading to this first approval. |
Which database exists that contains regulatory sites for splicing in human basal ganglia? | Braineacv2 has been identified as a database that contains regulatory sites for splicing in human basal ganglia. | |
Should minocycline be used for mild Alzheimer disease? | No. Minocycline did not delay the progress of cognitive or functional impairment in people with mild Alzheimer disease during a 2-year period. | IMPORTANCE: There are no disease-modifying treatments for Alzheimer disease
(AD), the most common cause of dementia. Minocycline is anti-inflammatory,
protects against the toxic effects of β-amyloid in vitro and in animal models of
AD, and is a credible repurposed treatment candidate.
OBJECTIVE: To determine whether 24 months of minocycline treatment can modify
cognitive and functional decline in patients with mild AD.
DESIGN, SETTING, AND PARTICIPANTS: Participants were recruited into a
double-blind randomized clinical trial from May 23, 2014, to April 14, 2016,
with 24 months of treatment and follow-up. This multicenter study in England and
Scotland involved 32 National Health Service memory clinics within secondary
specialist services for people with dementia. From 886 screened patients, 554
patients with a diagnosis of mild AD (Standardised Mini-Mental State Examination
[sMMSE] score ≥24) were randomized.
INTERVENTIONS: Participants were randomly allocated 1:1:1 in a semifactorial
design to receive minocycline (400 mg/d or 200 mg/d) or placebo for 24 months.
MAIN OUTCOMES AND MEASURES: Primary outcome measures were decrease in sMMSE
score and Bristol Activities of Daily Living Scale (BADLS), analyzed by
intention-to-treat repeated-measures regression.
RESULTS: Of 544 eligible participants (241 women and 303 men), the mean (SD) age
was 74.3 (8.2) years, and the mean (SD) sMMSE score was 26.4 (1.9). Fewer
participants completed 400-mg minocycline hydrochloride treatment (28.8% [53 of
184]) than 200-mg minocycline treatment (61.9% [112 of 181]) or placebo (63.7%
[114 of 179]; P < .001), mainly because of gastrointestinal symptoms (42 in the
400-mg group, 15 in the 200-mg group, and 10 in the placebo group; P < .001),
dermatologic adverse effects (10 in the 400-mg group, 5 in the 200-mg group, and
1 in the placebo group; P = .02), and dizziness (14 in the 400-mg group, 3 in
the 200-mg group, and 1 in the placebo group; P = .01). Assessment rates were
lower in the 400-mg group: 68.4% (119 of 174 expected) for sMMSE at 24 months
compared with 81.8% (144 of 176) for the 200-mg group and 83.8% (140 of 167) for
the placebo group. Decrease in sMMSE scores over 24 months in the combined
minocycline group was similar to that in the placebo group (4.1 vs 4.3 points).
The combined minocycline group had mean sMMSE scores 0.1 points higher than the
placebo group (95% CI, -1.1 to 1.2; P = .90). The decrease in mean sMMSE scores
was less in the 400-mg group than in the 200-mg group (3.3 vs 4.7 points;
treatment effect = 1.2; 95% CI, -0.1 to 2.5; P = .08). Worsening of BADLS scores
over 24 months was similar in all groups: 5.7 in the 400-mg group, 6.6 in the
200-mg group, and 6.2 in the placebo groups (treatment effect for minocycline vs
placebo = -0.53; 95% CI, -2.4 to 1.3; P = .57; treatment effect for 400 mg vs
200 mg of minocycline = -0.31; 95% CI, -0.2 to 1.8; P = .77). Results were
similar in different patient subgroups and in sensitivity analyses adjusting for
missing data.
CONCLUSIONS AND RELEVANCE: Minocycline did not delay the progress of cognitive
or functional impairment in people with mild AD during a 2-year period. This
study also found that 400 mg of minocycline is poorly tolerated in this
population.
TRIAL REGISTRATION: isrctn.org Identifier: ISRCTN16105064. |
What is pyroptosis? | Pyroptosis is an inflammatory form of cell death triggered by certain inflammasomes, leading to the cleavage of gasdermin D (GSDMD) and activation of inactive cytokines like IL-18 and IL-1β. Pyroptosis has been reported to be closely associated to some diseases like atherosclerosis and diabetic nephropathy. Recently, some studies found that pyroptosis can influence the proliferation, invasion and metastasis of tumor, which regulated by some non-coding RNAs and other molecules. | Pyroptosis is a pro-inflammatory form of programmed cell death, whose genesis
directly depended on caspase-1 activation. Pulmonary hypertension (PH) is a
disease characterized, in part, by vascular fibrosis. Up to now, there is no
report on the relationship between pyroptosis and vascular fibrosis in PH. Here,
we confirmed that pyroptosis had occurred in the media of pulmonary arteries in
two PH rat models and hypoxic human pulmonary arterial smooth muscle cells
(hPASMCs). Caspase-1 inhibition attenuated the pathogenesis of PH, as assessed
by vascular remodeling, right ventricular systolic pressure, right ventricle
hypertrophy and hemodynamic parameters of pulmonary vasculature. Moreover,
caspase-1 inhibition suppressed pulmonary vascular fibrosis as demonstrated by
Masson staining, as well as immunohistochemistry and Western blot analysis of
fibrillar collagen. In addition, Programmed death-ligand 1 (PD-L1) was markedly
increased in PH, which was regulated by the transcription factor STAT1.
Furthermore, PD-L1 knockdown in hPASMCs repressed the onset of hypoxia-induced
pyroptosis and fibrosis. Overall, these data identify a critical STAT1-dependent
posttranscriptional modification that promotes PD-L1 expression in the
pyroptosis of PASMCs to modulate pulmonary vascular fibrosis and accelerate the
progression of PH. Pyroptosis is a type of programmed lytic cell death that could be activated by
either the canonical or noncanonical inflammasome pathway. In this study, we
aimed to examine the effect of hypertonic solution on noncanonical pyroptosis in
macrophage. We found that although hypertonic solution had a general inhibitory
effect on noncanonical pyroptosis, the underlying mechanism varied by the solute
causing hypertonicity. Specifically, hypertonic NaCl or KCl solution inhibited
the cleavage of gasdermin D, the pore-forming protein in pyroptosis, whereas
hypertonic saccharide solution did not affect the cleavage or membrane binding
of gasdermin D. In this case, nevertheless, pyroptosis was still inhibited as
evidenced by the preserved mitochondria activity and cell membrane permeability. |
What is a HapMap | HapMap is a international effort for creating an annotated haplotype map of the world’s most commonhaplotype sequences. | Understanding of linkage disequilibrium (LD) in human populations could
facilitate the discovery of genes that influence complex human diseases. The
"HapMap" project is now underway to characterize patterns of LD in the human
genome. A pilot study showed "haplotype blocks" in 51 regions scattered
throughout the genome. These intriguing results raise important questions about
the nature of recombination, and highlight practical issues of marker
collection, the influence of statistical modelling on apparent block structure,
and the levels of genotyping necessary for studies of common diseases. Knowledge
of local disequilibrium patterns may help identify common polymorphisms involved
in complex disease, but completely new analytical methods and experimental
designs will be required to identify important rare variants. The goal of the International HapMap Project is to determine the common patterns
of DNA sequence variation in the human genome and to make this information
freely available in the public domain. An international consortium is developing
a map of these patterns across the genome by determining the genotypes of one
million or more sequence variants, their frequencies and the degree of
association between them, in DNA samples from populations with ancestry from
parts of Africa, Asia and Europe. The HapMap will allow the discovery of
sequence variants that affect common disease, will facilitate development of
diagnostic tools, and will enhance our ability to choose targets for therapeutic
intervention. One of the goals of the International HapMap Project is the identification of
common haplotypes in genes. However, HapMap uses an incomplete catalogue of
single nucleotide polymorphisms (SNPs) and might miss some common haplotypes. We
examined this issue using data from the Environmental Genome Project (EGP) which
resequenced 335 genes in 90 people, and thus, has a nearly complete catalogue of
gene SNPs. The EGP identified a total of 45,243 SNPs, of which 10,780 were
common SNPs (minor allele frequency >or=0.1). Using EGP common SNP genotype
data, we identified 1,459 haplotypes with frequency >or=0.05 and we use these as
"benchmark" haplotypes. HapMap release 16 had genotype information for 1,573 of
10,780 (15%) EGP common SNPs. Using these SNPs, we identified common HapMap
haplotypes (frequency >or=0.05) in each of the four HapMap ethnic groups. To
compare common HapMap haplotypes to EGP benchmark haplotypes, we collapsed
benchmark haplotypes to the set of 1,573 SNPs. Ninety-eight percent of the
collapsed benchmark haplotypes could be found as common HapMap haplotypes in one
or more of the four HapMap ethnic groups. However, collapsing benchmark
haplotypes to the set of SNPs available in HapMap resulted in a loss of
haplotype information: 545 of 1,459 (37%) benchmark haplotypes were uniquely
identified, and only 25% of genes had all their benchmark haplotypes uniquely
identified. We resampled the EGP data to examine the effect of increasing the
number of HapMap SNPs to 5 million, and estimate that approximately 40% of
common SNPs in genes will be sampled and that half of the genes will have
sufficient SNPs to identify all common haplotypes. This inability to distinguish
common haplotypes of genes may result in loss of power when examining
haplotype-disease association. BACKGROUND: The recent advancement in human genome sequencing and genotyping has
revealed millions of single nucleotide polymorphisms (SNP) which determine the
variation among human beings. One of the particular important projects is The
International HapMap Project which provides the catalogue of human genetic
variation for disease association studies. In this paper, we analyzed the
genotype data in HapMap project by using National Institute of Environmental
Health Sciences Environmental Genome Project (NIEHS EGP) SNPs. We first
determine whether the HapMap data are transferable to the NIEHS data. Then, we
study how well the HapMap SNPs capture the untyped SNPs in the region. Finally,
we provide general guidelines for determining whether the SNPs chosen from
HapMap may be able to capture most of the untyped SNPs.
RESULTS: Our analysis shows that HapMap data are not robust enough to capture
the untyped variants for most of the human genes. The performance of SNPs for
European and Asian samples are marginal in capturing the untyped variants, i.e.
approximately 55%. Expectedly, the SNPs from HapMap YRI panel can only capture
approximately 30% of the variants. Although the overall performance is low,
however, the SNPs for some genes perform very well and are able to capture most
of the variants along the gene. This is observed in the European and Asian
panel, but not in African panel. Through observation, we concluded that in order
to have a well covered SNPs reference panel, the SNPs density and the
association among reference SNPs are important to estimate the robustness of the
chosen SNPs.
CONCLUSION: We have analyzed the coverage of HapMap SNPs using NIEHS EGP data.
The results show that HapMap SNPs are transferable to the NIEHS SNPs. However,
HapMap SNPs cannot capture some of the untyped SNPs and therefore resequencing
may be needed to uncover more SNPs in the missing region. HapMap provides linkage disequilibrium (LD) information on a sample of 3.7
million SNPs that can be used for tag SNP selection in whole-genome association
studies. HapMap can also be used for tag SNP selection in candidate genes,
although its performance has yet to be evaluated against gene resequencing data,
where there is near-complete SNP ascertainment. The Environmental Genome Project
(EGP) is the largest gene resequencing effort to date with over 500 resequenced
genes. We used HapMap data to select tag SNPs and calculated the proportions of
common SNPs (MAF>or=0.05) tagged (rho2>or=0.8) for each of 127 EGP Panel 2 genes
where individual ethnic information was available. Median gene-tagging
proportions are 50, 80 and 74% for African, Asian, and European groups,
respectively. These low gene-tagging proportions may be problematic for some
candidate gene studies. In addition, although HapMap targeted nonsynonymous SNPs
(nsSNPs), we estimate only approximately 30% of nonsynonymous SNPs in EGP are in
high LD with any HapMap SNP. We show that gene-tagging proportions can be
improved by adding a relatively small number of tag SNPs that were selected
based on resequencing data. We also demonstrate that ethnic-mixed data can be
used to improve HapMap gene-tagging proportions, but are not as efficient as
ethnic-specific data. Finally, we generalized the greedy algorithm proposed by
Carlson et al (2004) to select tag SNPs for multiple populations and implemented
the algorithm into a freely available software package mPopTag. The approach to epilepsy care has transformed in the last 30 years, with more
and better anti-epileptic medications, improved cerebral imaging and increased
surgical options. Alongside this, developments in neuroscience and molecular
genetics have furthered the understanding of epileptogenesis. Future
developments in pharmacogenomics hold the promise of antiepileptic drugs matched
to specific genotypes. Despite this rapid progress, one-third of epilepsy
patients remain refractory to medication, with their seizures impacting upon
day-to-day activity, social well-being, independence, economic output and
quality of life. International genome collaborations, such as HapMap and the
Welcome Trust Case-Control Consortium single nucleotide polymorphism (SNP)
mapping project have identified common genetic variations in diseases of major
public health importance. Such genetic signposts should help to identify at-risk
populations with a view to producing more effective pharmaceutical treatments.
Neurological disorders, despite comprising one-fifth of UK acute medical
hospital admissions, are surprisingly under-represented in these projects.
Epilepsy is the commonest serious neurological disorder worldwide. Although
physically, psychologically, socially and ficially disabling, it rarely
receives deserved attention from physicians, scientists and governmental bodies.
As outlined in this article, research into epilepsy genetics presents unique
challenges. These help to explain why the identification of its complex genetic
traits has lagged well behind other disciplines, particularly the efforts made
in neuropsychiatric disorders. Clinical beginnings must underpin any genetic
understanding in epilepsy. Success in identifying genetic traits in other
disorders does not make the automatic case for genome-wide screening in
epilepsy, but such is a desired goal. The essential clinical approach of
accurately phenotyping, diagnosing and interpreting the dynamic nature of
epilepsy remains fundamental to harvesting its potential translational outcomes. MOTIVATION: Genome-wide association studies (GWAS) generate relationships
between hundreds of thousands of single nucleotide polymorphisms (SNPs) and
complex phenotypes. The contribution of the traditionally overlooked copy number
variations (CNVs) to complex traits is also being actively studied. To
facilitate the interpretation of the data and the designing of follow-up
experimental validations, we have developed a database that enables the sensible
prioritization of these variants by combining several approaches, involving not
only publicly available physical and functional annotations but also multilocus
linkage disequilibrium (LD) annotations as well as annotations of expression
quantitative trait loci (eQTLs).
RESULTS: For each SNP, the SCAN database provides: (i) summary information from
eQTL mapping of HapMap SNPs to gene expression (evaluated by the Affymetrix exon
array) in the full set of HapMap CEU (Caucasians from UT, USA) and YRI (Yoruba
people from Ibadan, Nigeria) samples; (ii) LD information, in the case of a
HapMap SNP, including what genes have variation in strong LD (pairwise or
multilocus LD) with the variant and how well the SNP is covered by different
high-throughput platforms; (iii) summary information available from public
databases (e.g. physical and functional annotations); and (iv) summary
information from other GWAS. For each gene, SCAN provides annotations on: (i)
eQTLs for the gene (both local and distant SNPs) and (ii) the coverage of all
variants in the HapMap at that gene on each high-throughput platform. For each
genomic region, SCAN provides annotations on: (i) physical and functional
annotations of all SNPs, genes and known CNVs within the region and (ii) all
genes regulated by the eQTLs within the region.
AVAILABILITY: http://www.scandb.org.
SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics
online. The International Haplotype Map Project (HapMap) has provided an essential
database for studies of human population genetics and genome-wide association.
Phases I and II of the HapMap project generated genotype data across ∼3 million
SNP loci in 270 individuals representing four populations. Phase III provides
dense genotype data on ∼1.5 million SNPs, generated by Illumina and Affymetrix
platforms in a larger set of individuals. Release 3 of phase III of the HapMap
contains 1397 individuals from 11 populations, including 250 of the original 270
phase I and phase II individuals and 1147 additional individuals. Although some
known relationships among the phase III individuals have been described in the
data release, the genotype data that are currently available provide an
opportunity to empirically ascertain previously unknown relationships. We
performed a systematic analysis of genetic relatedness and were able not only to
confirm the reported relationships, but also to detect numerous additional,
previously unidentified pairs of close relatives in the HapMap sample. The
inferred relative pairs make it possible to propose standardized subsets of
unrelated individuals for use in future studies in which relatedness needs to be
clearly defined. BACKGROUND: Since publication of the human genome in 2003, geneticists have been
interested in risk variant associations to resolve the etiology of traits and
complex diseases. The International HapMap Consortium undertook an effort to
catalog all common variation across the genome (variants with a minor allele
frequency (MAF) of at least 5% in one or more ethnic groups). HapMap along with
advances in genotyping technology led to genome-wide association studies which
have identified common variants associated with many traits and diseases. In
2008 the 1000 Genomes Project aimed to sequence 2500 individuals and identify
rare variants and 99% of variants with a MAF of <1%.
METHODS: To determine whether the 1000 Genomes Project includes all the variants
in HapMap, we examined the overlap between single nucleotide polymorphisms
(SNPs) genotyped in the two resources using merged phase II/III HapMap data and
low coverage pilot data from 1000 Genomes.
RESULTS: Comparison of the two data sets showed that approximately 72% of HapMap
SNPs were also found in 1000 Genomes Project pilot data. After filtering out
HapMap variants with a MAF of <5% (separately for each population), 99% of
HapMap SNPs were found in 1000 Genomes data.
CONCLUSIONS: Not all variants cataloged in HapMap are also cataloged in 1000
Genomes. This could affect decisions about which resource to use for SNP
queries, rare variant validation, or imputation. Both the HapMap and 1000
Genomes Project databases are useful resources for human genetics, but it is
important to understand the assumptions made and filtering strategies employed
by these projects. The rapidly growing amount of genomic sequence data being generated and made
publicly available necessitate the development of new data storage and archiving
methods. The vast amount of data being shared and manipulated also create new
challenges for network resources. Thus, developing advanced data compression
techniques is becoming an integral part of data production and analysis. The
HapMap project is one of the largest public resources of human single-nucleotide
polymorphisms (SNPs), characterizing over 3 million SNPs genotyped in over 1000
individuals. The standard format and biological properties of HapMap data
suggest that a dedicated genetic compression method can outperform generic
compression tools. We propose a compression methodology for genetic data by
introducing HapZipper, a lossless compression tool tailored to compress HapMap
data beyond benchmarks defined by generic tools such as gzip, bzip2 and lzma. We
demonstrate the usefulness of HapZipper by compressing HapMap 3 populations to
<5% of their original sizes. HapZipper is freely downloadable from
https://bitbucket.org/pchanda/hapzipper/downloads/HapZipper.tar.bz2. |
Which cancer types are associated with mutations in the TWIST1 gene? | Loss-of-function mutations of TWIST1, a catalytic component of polycomb repressive complex 1, are observed in ~\n10% of all human cancers, including gastric, non-small cell lung, breast ductal carcinoma, nonsmall cell lung cancer, prostate cancer, ovarian cancer, breast tumor, papillary thyroid cancer, and gastric cancer. | The Saethre-Chotzen syndrome is an autosomal, domitly inherited
craniosynostosis caused by mutations in the basic helix-loop-helix transcription
factor gene TWIST1. This syndrome has hitherto not been associated with an
increased risk of cancer. However, recent studies, using a murine breast tumor
model, have shown that Twist may act as a key regulator of metastasis and that
the gene is overexpressed in subsets of sporadic human breast cancers. Here, we
report a novel association between the Saethre-Chotzen syndrome and breast
cancer. In 15 Swedish Saethre-Chotzen families, 15 of 29 (52%) women carriers
over the age of 25 had developed breast cancer. At least four patients developed
breast cancer before 40 years of age, and five between 40 and 50 years of age.
The observed cases with breast cancer (n = 15) are significantly higher than
expected (n = 0.89), which gives a standardized incidence ratio (SIR) of 16.80
(95% CI 1.54-32.06). Our finding of a high frequency of breast cancer in women
with the Saethre-Chotzen syndrome identifies breast cancer as an important and
previously unrecognized symptom characteristic of this syndrome. The results
strongly suggest that women carriers of this syndrome would benefit from genetic
counseling and enrolment in surveillance programs including yearly mammography.
Our results also indicate that the TWIST1 gene may be a novel breast cancer
susceptibility gene. Additional studies are, however, necessary to reveal the
mechanism by which TWIST1 may predispose to early onset breast cancer in
Saethre-Chotzen patients. Saethre-Chotzen syndrome is one of the most common craniosynostosis syndromes.
It is an autosomal domitly inherited disorder with variable expression that
is caused by germline mutations in the TWIST1 gene or more rarely in the FGFR2
or FGFR3 genes. We have previously reported that patients with Saethre-Chotzen
syndrome have an increased risk of developing breast cancer. Here we have
analysed a cohort of 26 women with BRCA1/2-negative hereditary breast cancer to
study whether a proportion of these families might have mutations in
Saethre-Chotzen-associated genes. DNA sequence analysis of TWIST1 showed no
pathogenic mutations in the coding sequence in any of the 26 patients. MLPA
(multiplex ligation-dependent probe amplification)-analysis also showed no
alterations in copy numbers in any of the craniofacial disorder genes MSX2,
ALX4, RUNX2, EFNB1, TWIST1, FGFR1, FGFR2,FGFR3, or FGFR4. Taken together, our
findings indicate that mutations in Saethre-Chotzen-associated genes are
uncommon or absent in BRCA1/2-negative patients with hereditary breast cancer. Twist1, a basic helix-loop-helix transcription factor, promotes breast tumor
cell epithelial-mesenchymal transition (EMT), invasiveness, and metastasis.
However, the mechanisms responsible for regulating Twist1 stability are unknown
in these cells. We identified the serine 68 (Ser 68) as a major phosphorylation
site of Twist1 by mass spectrometry and with specific antibodies. This Ser 68 is
phosphorylated by p38, c-Jun N-terminal kinases (JNK), and extracellular
signal-regulated kinases1/2 in vitro, and its phosphorylation levels positively
correlate with Twist1 protein levels in human embryonic kidney 293 and breast
cancer cells. Prevention of Ser 68 phosphorylation by an alanine (A) mutation
(Ser 68A) dramatically accelerates Twist1 ubiquitination and degradation.
Furthermore, activation of mitogen-activated protein kinases (MAPK) by an active
Ras protein or TGF-β treatment significantly increases Ser 68 phosphorylation
and Twist1 protein levels without altering Twist1 mRNA expression, whereas
blocking of MAPK activities by either specific inhibitors or domit negative
inhibitory mutants effectively reduces the levels of both induced and uninduced
Ser 68 phosphorylation and Twist protein. Accordingly, the mammary epithelial
cells expressing Twist1 exhibit much higher degrees of EMT and invasiveness on
stimulation with TGF-β or the active Ras and paclitaxel resistance compared with
the same cells expressing the Ser 68A-Twist1 mutant. Importantly, the levels of
Ser 68 phosphorylation in the invasive human breast ductal carcinomas positively
correlate with the levels of Twist1 protein and JNK activity and are
significantly higher in progesterone receptor-negative and HER2-positive breast
cancers. These findings suggest that activation of MAPKs by tyrosine kinase
receptors and Ras signaling pathways may substantially promote breast tumor cell
EMT and metastasis via phoshorylation and stabilization of Twist1. A large fraction of non-small cell lung cancers (NSCLC) are dependent on defined
oncogenic driver mutations. Although targeted agents exist for EGFR- and
EML4-ALK-driven NSCLCs, no therapies target the most frequently found driver
mutation, KRAS. Furthermore, acquired resistance to the currently targetable
driver mutations is nearly universally observed. Clearly a novel therapeutic
approach is needed to target oncogene-driven NSCLCs. We recently showed that the
basic helix-loop-helix transcription factor Twist1 cooperates with mutant Kras
to induce lung adenocarcinoma in transgenic mouse models and that inhibition of
Twist1 in these models led to Kras-induced senescence. In the current study, we
examine the role of TWIST1 in oncogene-driven human NSCLCs. Silencing of TWIST1
in KRAS-mutant human NSCLC cell lines resulted in dramatic growth inhibition and
either activation of a latent oncogene-induced senescence program or, in some
cases, apoptosis. Similar effects were observed in EGFR mutation-driven and
c-Met-amplified NSCLC cell lines. Growth inhibition by silencing of TWIST1 was
independent of p53 or p16 mutational status and did not require previously
defined mediators of senescence, p21 and p27, nor could this phenotype be
rescued by overexpression of SKP2. In xenograft models, silencing of TWIST1
resulted in significant growth inhibition of KRAS-mutant, EGFR-mutant, and
c-Met-amplified NSCLCs. Remarkably, inducible silencing of TWIST1 resulted in
significant growth inhibition of established KRAS-mutant tumors. Together these
findings suggest that silencing of TWIST1 in oncogene driver-dependent NSCLCs
represents a novel and promising therapeutic strategy. TGF-β1 induces epithelial-mesenchymal transition (EMT) to stimulate cancer cell
progression, and TWIST1 is a critical regulator of EMT. In the present study, we
determined the underlying mechanisms of TGF-β1-induced TWIST1 expression and its
effect on prostate cancer cell invasion. TGF-β1 stimulated STAT3 phosphorylation
and HIF-1α expression. Silencing either STAT3 or HIF-1α efficiently attenuated
TGF-β1-induced TWIST1 expression. Further ectopic expression of a domit
negative mutant of STAT3 reduced TGF-β1-induced TWIST1 expression. In addition,
STAT3 and HIF-1α up-regulated TWIST1 expression by direct binding to a TWIST1
promoter. Strikingly, STAT3 also enhanced TGF-β1-induced TWIST1 expression
through HIF-1α stabilization. Collectively, we demonstrate a mechanistic cascade
of TGF-β1 up-regulating STAT3 activation and HIF-1α stabilization and subsequent
TWIST1 expression, leading to prostate cancer invasion. Cancer-associated fibroblasts (CAF) are key contributors to maligt
progression, but their critical regulators remain largely unknown. In this
study, we examined the role of Twist1, a central regulator of
epithelial-mesenchymal transition in carcinoma cells, in the
transdifferentiation of normal quiescent fibroblasts to CAF and we defined its
upstream controls and downstream effectors. Primary human gastric fibroblast and
CAF cultures were established from gastrectomy specimens and validated as
nontumor cells by somatic mutation analyses. In these cultures, exposure to the
proinflammatory cytokine IL6 commonly expressed in tumors was sufficient to
induce Twist1 expression in normal fibroblasts and transdifferentiate them into
CAFs via STAT3 phosphorylation. In xenograft models, tumor infiltration of
Twist1-expressing CAFs was enhanced strongly by ectopic IL6 expression in
gastric or breast cancer cells. We found that Twist1 expression was necessary
and sufficient for CAF transdifferentiation. Enforced expression of Twist1 in
normal fibroblasts was also sufficient to drive CAF marker expression and
maligt character in gastric cancer cells both in vitro and in vivo.
Conversely, silencing the expression of Twist1 in CAFs abrogated their
tumor-promoting properties. Downstream of Twist1, we defined the chemokine
CXCL12 as a transcriptional target. Clinically, CXCL12 and Twist1 expression
were correlated in CAFs present in gastric tumor specimens. Finally, ectopic
expression of Twist1 in normal fibroblasts suppressed premature senescence,
whereas Twist1 attenuation accelerated senescence in CAFs. Our findings define
Twist1 as a compelling target to deprogram the tumor-supporting features of the
cancer microenvironment. Author information:
(1)Department of Radiation Oncology and Molecular Radiation Sciences, Sidney
Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine,
Baltimore, MD, USA.
(2)The Russell H. Morgan Department of Radiology and Radiological Science,
Division of Cancer Imaging Research, Johns Hopkins University School of
Medicine, Baltimore, MD, USA; Department of Oncology, Sidney Kimmel
Comprehensive Cancer Center, Johns Hopkins University School of Medicine,
Baltimore, MD, USA; In Vivo Cellular and Molecular Imaging Center, Johns Hopkins
University School of Medicine, Baltimore, MD, USA.
(3)Department of Radiation Oncology and Molecular Radiation Sciences, Sidney
Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine,
Baltimore, MD, USA; Cellular and Molecular Medicine Program, Johns Hopkins
University School of Medicine, Baltimore, MD, USA.
(4)Department of Environmental Health Sciences, Johns Hopkins University
Bloomberg School of Public Health, Baltimore, MD, USA.
(5)Department of Oncology, Division of Biostatistics and Bioinformatics, Sidney
Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine,
Baltimore, MD, USA.
(6)Department of Pediatrics, Riley Heart Research Center, Indiana University
School of Medicine, Indianapolis, IN, USA.
(7)Department of Medicine, Division of Hematology-Oncology, Hillman Cancer
Center, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
(8)In Vivo Cellular and Molecular Imaging Center, Johns Hopkins University
School of Medicine, Baltimore, MD, USA; Department of Environmental Health
Sciences, Johns Hopkins University Bloomberg School of Public Health, Baltimore,
MD, USA; Physical Sciences in Oncology Center, Johns Hopkins University,
Baltimore, MD, USA; Department of Chemical and Biomolecular Engineering, Johns
Hopkins University, Baltimore, MD, USA.
(9)Department of Radiation Oncology and Molecular Radiation Sciences, Sidney
Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine,
Baltimore, MD, USA; Department of Oncology, Sidney Kimmel Comprehensive Cancer
Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA; In Vivo
Cellular and Molecular Imaging Center, Johns Hopkins University School of
Medicine, Baltimore, MD, USA; Cellular and Molecular Medicine Program, Johns
Hopkins University School of Medicine, Baltimore, MD, USA; Department of
Urology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Electronic address: [email protected]. Twist1 is a transcription factor driving epithelial-mesenchymal transition,
invasion and metastasis of breast cancer cells. Mice with germ-line Twist1
knockout are embryonic lethal, while adult mice with inducible Twist1 knockout
have no obvious health problems, suggesting that Twist1 is a viable therapeutic
target for the inhibition of invasion and metastasis of breast cancer in adult
patients. In this study, we expressed a luciferase protein or a
Twist1-luciferase fusion protein in HeLa cells as part of a high throughput
system to screen 1280 compounds in the Library of Pharmacologically Active
Compounds (LOPAC) from Sigma-Aldrich for their effects on Twist1 protein
expression. One of the most interesting compounds identified is tamoxifen, a
selective estrogen receptor (ER) modulator used to treat ER-positive breast
cancer. Tamoxifen treatment significantly accelerated Twist1 degradation in
multiple cell lines including HEK293 human kidney cells, 4T1 and 168FARN mouse
mammary tumor cells with either ectopically or endogenously expressed Twist1.
Tamoxifen-induced Twist1 degradation could be blocked by the MG132 proteasome
inhibitor, suggesting that tamoxifen induces Twist1 degradation through the
ubiquitination-proteasome pathway. However, tamoxifen-induced Twist1 degradation
was independent of Twist1 mRNA expression, estrogen signaling and MAPK-mediated
Twist1 phosphorylation in these cells. Importantly, tamoxifen also significantly
inhibited invasive behavior in Matrigel and lung metastasis in SCID-bg mice of
ER-negative 4T1 mammary tumor cells, which depend on endogenous Twist1 to invade
and metastasize. These results indicate that tamoxifen can significantly
accelerate Twist1 degradation to suppress cancer cell invasion and metastasis,
suggesting that tamoxifen can be used not only to treat ER-positive breast
cancers but also to reduce Twist1-mediated invasion and metastasis in
ER-negative breast cancers. Transmembrane protease serine 4 (TMPRSS4), a type-II transmembrane serine
protease, is involved in the development and progression of wide range of
tumors. However, the biological role of TMPRSS4 in prostate cancer remains
obscure. Here, we investigated the effect of TMPRSS4 on proliferation and
migration in prostate cancer and potential mechanisms. Our findings demonstrated
over-expression of TMPRSS4 promoted the PC3 prostate cancer cells migration,
which could be reversed by TMPRSS4 silencing. TMPRSS4 induced TWIST1 expression
and followed progression of EMT along with upregulation of N-cadherin and
downregulation of E-cadherin via STAT3 phosphorylation. Silencing TWIST1
significantly attenuated TMPRSS4-induced PC3 migration. Moreover, knockdown of
STAT3 effectively attenuated TMPRSS4-induced TWIST1 expression and TWIST1
promoter activity. Taken together, we demonstrated a mechanistic cascade of
TMPRSS4 up-regulating STAT3 activation and subsequent TWIST1 expression, leading
to prostate cancer migration. TWIST1, an epithelial-mesenchymal transition (EMT) transcription factor, is
critical for oncogene-driven non-small cell lung cancer (NSCLC) tumorigenesis.
Given the potential of TWIST1 as a therapeutic target, a chemical-bioinformatic
approach using connectivity mapping (CMAP) analysis was used to identify TWIST1
inhibitors. Characterization of the top ranked candidates from the unbiased
screen revealed that harmine, a harmala alkaloid, inhibited multiple TWIST1
functions, including single-cell dissemination, suppression of normal branching
in 3D epithelial culture, and proliferation of oncogene driver-defined NSCLC
cells. Harmine treatment phenocopied genetic loss of TWIST1 by inducing
oncogene-induced senescence or apoptosis. Mechanistic investigation revealed
that harmine targeted the TWIST1 pathway through its promotion of TWIST1 protein
degradation. As dimerization is critical for TWIST1 function and stability, the
effect of harmine on specific TWIST1 dimers was examined. TWIST1 and its dimer
partners, the E2A proteins, which were found to be required for TWIST1-mediated
functions, regulated the stability of the other heterodimeric partner
posttranslationally. Harmine preferentially promoted degradation of the
TWIST1-E2A heterodimer compared with the TWIST-TWIST1 homodimer, and targeting
the TWIST1-E2A heterodimer was required for harmine cytotoxicity. Finally,
harmine had activity in both transgenic and patient-derived xenograft mouse
models of KRAS-mutant NSCLC. These studies identified harmine as a
first-in-class TWIST1 inhibitor with marked anti-tumor activity in
oncogene-driven NSCLC including EGFR mutant, KRAS mutant and MET altered
NSCLC.Implications: TWIST1 is required for oncogene-driven NSCLC tumorigenesis
and EMT; thus, harmine and its analogues/derivatives represent a novel
therapeutic strategy to treat oncogene-driven NSCLC as well as other solid tumor
maligcies. Mol Cancer Res; 15(12); 1764-76. ©2017 AACR. BACKGROUND: Metastatic castration-resistant prostate cancer (mCRPC) is one of
the main contributors to the death of prostate cancer patients. To date, the
detailed molecular mechanisms underlying mCRPC are unclear. Given the crucial
role of epithelial-mesenchymal transition (EMT) in cancer metastasis, we aimed
to analyse the expression and function of Transforming growth factor-beta
(TGF-β) signal-associated protein named Sox5 in mCRPC.
METHODS: The protein expression levels were analysed by western blot,
immunohistochemistry and immunofluorescence. Luciferase reporter assays and
chromatin immunoprecipitation were employed to validate the target of Sox5. The
effect of Smad3/Sox5/Twist1 on PCa progression was investigated in vitro and in
vivo.
RESULTS: Here, we found that TGF-β-induced EMT was accompanied by increased Sox5
expression. Interestingly, knockdown of Sox5 expression attenuated EMT induced
by TGF-β signalling. Furthermore, we demonstrated that Smad3 could bind to the
promoter of Sox5 and regulate its expression. Mechanistically, Sox5 could bind
to Twist1 promoter and active Twist1, which initiated EMT. Importantly,
knockdown of Sox5 in prostate cancer cells resulted in less of the mesenchymal
phenotype and cell migration ability. Furthermore, targeting Sox5 could inhibit
prostate cancer progression in a xenograft mouse model. In clinic, patients with
high Sox5 expression were more likely to suffer from metastases, and high Sox5
expression also has a lower progression-free survival and cancer
specific-survival in clinic database.
CONCLUSIONS: Therefore, we propose a new mechanism in which Smad3/Sox5/Twist1
promotes EMT and contributes to PCa progression. |
What did the RESILIENT study investigate? | A global, randomized, double-blind placebo-controlled study was conducted to confirm that BYM338 (bimagrumab), an anti-activin type II receptor antibody, improves motor function in patients with sporadic inclusion body myositis after 52 weeks' treatment consisting of intravenous administration every 4 weeks at doses of 10, 3, and 1 mg/kg. | A global, randomized, double-blind placebo-controlled study was conducted to
confirm that BYM338 (bimagrumab), an anti-activin type II receptor antibody,
improves motor function in patients with sporadic inclusion body myositis after
52 weeks' treatment consisting of intravenous administration every 4 weeks at
doses of 10, 3, and 1 mg/kg. In a Japanese sub-population (20 patients in total,
5 per dose group), no significant differences in the change from baseline of the
6-minute walking distance at Week 52 (primary endpoint) were observed between
the placebo group and each BYM338 dose group. Furthermore, the lean body mass as
an indicator of skeletal muscle mass increased in all BYM338 groups compared
with the placebo group and the effects were dose-dependent. Overall, the
Japanese sub-population showed similar trends as observed in the entire
population (251 patients in total). |
List features of the Thrombotic Thrombocytopenic Purpura pentad. | Thrombotic thrombocytopenic purpura (TTP) is typically characterized by the symptomatic pentad of fever, thrombocytopenia, microangiopathic hemolytic anemia, neurologic abnormalities, and renal failure. | Thrombotic thrombocytopenic purpura (TTP) is characterized by the pentad of
fever, thrombocytopenia, microangiopathic hemolytic anemia, fluctuating
neurologic symptoms, and renal dysfunction. Thrombotic thrombocytopenic purpura
has recently been reported in association with rheumatic diseases (RDs). The
authors present a patient with TTP and polymyositis and speculate on the
pathophysiology linking these two conditions. Thrombotic thrombocytopenic
purpura and RDs may present with overlapping clinical and laboratory features.
It is important to identify TTP as a cause of thrombocytopenia and hemolysis
when occurring in patients with RDs since management, treatment, and prognosis
differ. Early recognition and prompt institution of plasmapheresis may improve
the outcome in patients with TTP. Once formerly thought to be a rare disorder, thrombotic thrombocytopenic purpura
(TTP) is becoming increasingly recognized. It is characterized by a pentad of
clinical findings, including microangiopathic hemolytic anemia, thrombocytopenic
purpura, neurologic and renal abnormalities, and fever. Following a case report,
the major clinical findings, pathophysiologic findings, diagnoses, and use of
various therapeutic modalities are discussed. Thrombotic thrombocytopenic purpura is a clinical syndrome defined by the pentad
of thrombocytopenia, microangiopathic hemolytic anemia, fever, and renal and
neurologic abnormalities. The pathogenesis of this syndrome remains enigmatic,
though appropriate management usually involves plasma administration. The
authors report on an alternative therapy, high-dose intravenous immunoglobulin,
used in the patient after the failure of plasmapheresis. The implications and
potential applications of this therapy are discussed. Thrombotic thrombocytopenic purpura (TTP) is a syndrome characterised by the
clinical pentad of microangiopathic haemolytic anaemia (MAHA), thrombocytopenia,
renal failure, fluctuating neurologic signs, and fever. The aetiology of TTP is
unknown, but associations with various underlying diseases, infections and drugs
have been identified. One of these associations is with HIV infection. We
describe the clinical picture, the laboratory results and the response to plasma
therapy of two cases of HIV-associated TTP. In both patients, a longitudinal
semiquantitative assessment of the numbers of schistocytes in blood was made,
which correlated well with the more traditional parameters of disease activity.
Since 1987, at least 49 patients with HIV-associated TTP have been reported. A
case-analysis of the 38 patients who were described in sufficient detail and a
review of the literature in the setting of HIV infection is presented. The most
important conclusions from these combined data are: (1) TTP usually seems to
occur in patients with a CD4+ lymphocyte count < 250 x 10(6).l(-1); (2) more
than 50% of the patients present with TTP soon after or during an infectious or
maligt disease; (3) plasma exchange is the therapy of choice, still resulting
in mortality of 22%; (4) higher initial platelet count and creatinine level are
correlated with an adverse outcome. The pentad of thrombocytopenia, haemolytic anaemia, mild renal dysfunction,
neurological signs and fever, classically characterizes the syndrome of
thrombotic thrombocytopenic purpura (TTP). TTP usually occurs in adults but also
children have been described with this condition. The disorder may take a
relapsing course, termed chronic relapsing TTP (CRTTP), which although very
rare, may also begin in childhood. Deficiency of a recently identified enzyme,
the von Willebrand factor (vWF)-cleaving protease, seems to play a major role in
the development of TTP. We report on a 3-year-old boy with a dramatic but
typical clinical course of CRTTP. At the time of diagnosis, neurological
deficits and multiple cerebral infarctions had already occurred. In plasma,
vWF-cleaving protease was completely absent, both during acute TTP and in
remission. There was no protease inhibitor detected. Regular infusions of fresh
frozen plasma were successfully given for replacement on a prophylactic basis.
CONCLUSION: Assay of von Willebrand factor-cleaving protease helps to diagnose a
form of thrombotic thrombocytopenic purpura which may be managed by prophylactic
treatment with fresh frozen plasma. Clinical thrombotic thrombocytopenic purpura (TTP) is characterized by a pentad
of microangiopathic hemolytic anemia, thrombocytopenia, neurological symptoms,
renal involvement, and fever. A case of TTP in which early symptoms and signs
were suggestive of ischemic heart disease, renal failure, and severe
thrombocytopenia developed to a rapid outcome of death. The postmortem
examination revealed coronary artery microthrombi, typical of TTP. The clinical
presentation of this TTP was atypical: severe thrombocytopenia, striking renal
and CNS symptoms were present, but fever and anemia were not present. Thrombotic
thrombocytopenic purpura is an uncommon condition that carries a high fatality
rate if untreated. Awareness of this syndrome and its high risk of sudden death
underlines the importance of rapid diagnosis and treatment. Thrombotic thrombocytopenic purpura (TTP) is a rare clinical entity. It is a
multi-systemic disorder characterized by a clinical pentad of thrombocytopenia,
microangiopathic hemolytic anemia, diffuse and nonfocal neurologic symptoms,
decreased renal function, and fever. Abdominal pain is an uncommon presenting
symptom for TTP. Pancreatitis may occur from TTP or, in a few cases, may trigger
TTP. The clinical diagnosis of TTP is generally difficult because there are many
varied clinical presentations and the full expression of the pentad may be
prolonged. However, once the diagnosis is suspected or confirmed, immediate
plasmapherseis with plasma exchange must be performed to reduce the severe
morbidity from neurologic disability. BACKGROUND: The pentad of thrombocytopenia, hemolytic anemia, mild renal
dysfunction, neurologic signs, and fever, classically characterizes the syndrome
of thrombotic thrombocytopenic purpura (TTP). TTP usually occurs in adults as an
acquired form but a congenital form in children has also been described. In the
latter case, the initial presentation is often with neonatal jaundice and
thrombocytopenia. The disorder may subsequently take a relapsing course.
Deficiency of a recently identified novel metalloprotease, the von Willebrand
factor (vWF)-cleaving protease, originating from mutations in the ADAMTS13 gene
plays a major role in the development of TTP.
METHODS: Blood for DNA analysis was collected from six unrelated TTP families,
consisting of nine patients from four different countries, and was screened for
mutations in the ADAMTS13 gene. This gene spans 29 exons encompassing
approximately 37 kb. Conventional techniques of DNA extraction, polymerase chain
reaction (PCR), and direct cycle sequencing were used.
RESULTS: Eight novel ADAMTS13 mutations are presented. Half of the total number
of mutant ADAMTS13 alleles are amino acid substitutions. The disease-causing
mutations are spread over the gene. The pathogenicity of the individual
mutations is based upon their predicted effect on the ADAMTS13 protein and
segregation in family members. Although most of the patients (seven out of nine)
had symptoms during the neonatal period, they were in a remarkably good
condition. Only one of the nine patients had a decreased glomerular filtration
rate (GFR) with proteinuria and hematuria. Another patient had epileptic
seizures.
CONCLUSION: We confirm that deficiency of ADAMTS13 is a molecular mechanism
responsible for familial TTP. An early diagnosis allows prophylactic treatment
with fresh plasma infusions. Thrombotic thrombocytopenic purpura (TTP) is a rapidly progressive hematological
syndrome defined by the pentad of thrombocytopenia, microangiopathic hemolytic
anemia, neurologic abnormalities, fever and renal dysfunction. TTP has been
associated with major surgical procedures and specific medications. However,
there is no known previously reported case in which acute TTP occurred after a
percutaneous coronary intervention (PCI). We report a case of TTP after a PCI,
that presented with the pentad of symptoms, as well as hepatitis and
pancreatitis. Thrombotic thrombocytopenic purpura (TTP) is an uncommon disorder characterized
by a pentad of microangiopathic hemolytic anemia, thrombocytopenia, renal
dysfunction, fever, and a fluctuating neurologic syndrome. Splenectomy is
performed for patients who are refractory to plasma therapy and for relapsing
TTP. We describe a case of a patient who died due to intramyocardial hemorrhage
after undergoing laparoscopic splenectomy for TTP resistant to treatment with
plasmapheresis. A 52-year-old woman was admitted with ecchymoses, low platelet
count, weakness of left face and upper extremity, and a presumptive diagnosis of
TTP. Vital signs were stable. White blood count was 7800/microL, hemoglobin 7.9
g/dL, and platelet count of 13,000/microL. Her basic metabolic panel and liver
function tests were normal. Further laboratory workup confirmed the diagnosis of
TTP. The patient was initially treated with plasmapheresis and high dose steroid
therapy but underwent an emergent laparoscopic splenectomy due to refractory
TTP. At the end of the uneventful procedure, the patient suffered a cardiac
arrest and died. Autopsy concluded that the death was from myocardial failure
due to extensive myocardial hemorrhage secondary to TTP. There are several
published case reports of sudden death due to cardiac involvement in TTP.
However, intraoperative mortality is not reported. We conclude that TTP-related
acute heart failure may represent an extremely important clinical risk in these
patients who are undergoing surgery. Much has been learned about thrombotic thrombocytopenic purpura (TTP) and
heparin-induced thrombocytopenia (HIT) and much remains a diagnostic and
management challenge. While the pentad of thrombocytopenia, microangiopathic
hemolytic anemia, fever, and renal and neurologic abnormalities characterize the
clinical presentation of TTP, few patients present with all signs and symptoms.
Worse yet, the pentad and its components are seen in other so-called thrombotic
microangiopathies that demand different treatment approaches. HIT is another
systemic disorder presenting with thrombocytopenia and/or thrombosis with
potential devastating consequences whose diagnosis is difficult and management
is still evolving. Highlights of the conditions and clinical and laboratory
hints that allow physicians to diagnose TTP and HIT efficiently and offer
patients the best available therapeutic interventions are presented. Thrombotic thrombocytopenic purpura (TTP) is a severe disease, potentially
fatal, if not diagnosed and treated promptly. TTP is clinically characterized by
the pentad of thrombocytopenia, Coombs-negative hemolytic anemia, fever, renal
abnormalities and neurological disturbances. Advances in recent years have
delineated the molecular mechanisms of acquired and hereditary TTP.Many
infectious organisms have been reported to be associated with TTP, especially
mycoplasma, but few cases of Brucella infection associated with thrombotic
microangiopathy have been reported.We describe a young woman who presented with
TTP after acute infection with both Brucella melitensis and Brucella abortus.
The patient completely recovered following aggressive therapy with
plasmapharesis, high-dose corticosteroids and appropriate antimicrobial
therapy.Since measurement of ADAMTS13 activity and neutralizing antibodies is
now available, and none of the reported cases of brucellosis with thrombotic
microangiopathy (including the present report) were tested, for better
understanding of this rare association, we recommend this work-up in future
cases. CONTEXT: Acute pancreatitis due to thrombotic thrombocytopenic purpura is a well
recognized condition. Here, we are reporting a rare converse phenomenon, in
which thrombocytopenic purpura occurred secondary to acute pancreatitis.
CASE REPORT: A 19-year-old male referred to our intensive care unit with
diagnosis of acute pancreatitis with multi-organ dysfunction. He had history of
severe abdominal pain and recurrent vomiting about one month ago, requiring
hospital admission. There, on diagnostic work-up at admission, abdominal
ultrasonography was suggestive of pancreatitis. His serum amylase and lipase
were 1,900 and 1,582 U/L, respectively. Other laboratory parameters were within
normal limits. He was managed conservatively with intravenous fluids,
antibiotics and analgesics; and discharged after about 2 weeks One week after
discharge he was readmitted in same hospital with abdominal pain, multiple
episodes of bilious vomiting and abdominal distention. Later on he was referred
to our intensive care unit; having classical pentad of thrombocytopenic purpura,
i.e., thrombocytopenia, micro-angiopathic hemolytic anemia, renal failure,
encephalopathy, and fever. His condition improved with plasma exchange therapy
and transferred out from our ICU to ward after 10 days of stay.
CONCLUSION: Thrombocytopenic purpura may be precipitate by acute pancreatitis
due to multiple mechanisms. A high clinical suspicion is required to make an
early diagnosis and allow early initiation of plasma exchange therapy, resulting
in a good prognosis. A 36-year-old woman presented with abdominal pain followed by fever, confusion,
right sided weakness and nuchal rigidity. The investigation showed severe
anemia, thrombocytopenia and left middle cerebral artery (MCA) territory
infarction. The platelet was given before the lumbar puncture. After that, the
patient's clinical was deteriorating to quadriplegia and stuporous. Then the
patient was referred to Siriraj Hospital. The patient was diagnosed thrombotic
thrombocytopenic purpura (TTP) following pentad of clinical features:
microangiopathic hemolytic anemia, thrombocytopenia, fever neurologic, and renal
abnormalities. Magnetic resoce imaging (MRI) and magnetic resoce
angiography (MRA) of brain showed extensive bilateral MCA and mid basilar artery
stenosis. That was uncommon findings in TTP. The authors believed that platelet
transfusion made the clinical deterioration and develop extensive intracranial
vessels stenosis. Even the plasma exchange was performed but the neurological
symptoms did not improved. Finally, the patient succumbed from ventilator
associated pneumonia at 2 months after diagnosis. OBJECTIVE: To describe the clinical features, treatment and prognosis of
acquired thrombotic thrombocytopenic purpura (TTP) in children based on a single
institution experience.
METHODS: This study is a retrospective review of all 12 children with TTP seen
at New York Medical College- Westchester Medical Center during a period of 15 y
from 1993 to 2008.
RESULTS: There were 7 females and 5 males with acquired TTP, with a median age
of 13 (range, 6-17); and no cases of congenital TTP. The classic pentad of TTP
(microangiopathic hemolytic anemia, thrombocytopenia, neurologic symptoms, renal
dysfunction and fever) was seen in only three patients. Nine had renal
involvement; eight had neurologic symptoms; and four had fever. All 12 patients
had thrombocytopenia, anemia, and elevated LDH. Nine had idiopathic TTP. Three
patients had one of the following underlying disorders: systemic lupus
erythematosus, mixed connective tissue disorder, and aplastic anemia (post-bone
marrow transplant on cyclosporine). ADAMTS13 level was decreased in 7 of 8
patients studied. Eight of 10 patients achieved remission with plasmapheresis
alone. Two needed additional treatment before achieving remission. Two had one
or more relapses, requiring immunosupressive treatment with vincrisine,
prednisone, or rituximab. The patient with aplastic anemia died of pulmonary
hypertension 5 y after bone marrow transplantation. All other 11 patients are
alive and free of TTP for a median follow-up of 12 mo (range, 3-72 mo).
CONCLUSIONS: Acquired pediatric TTP responds well to plasmapheresis. However,
many patients do require additional treatment because of refractoriness to
plasmapheresis or relapse. The clinical features, response to treatment, and
relapse rate of pediatric TTP appear similar to those of adult TTP. Thrombotic thrombocytopenic purpura (TTP) consists of the pentad of
thrombocytopenia, hemolytic anemia, fever, neurologic abnormalities, and renal
disease. We present a case report of acute TTP following a bout of ischemic
colitis. This report reminds the clinician that ischemic colitis can be an
atypical presentation of TTP. The prompt recognition and treatment of this
disease process resulted in a good prognosis for our patient. Thrombotic thrombocytopenic purpura (TTP) is a multisystem disorder
characterized by a pentad consisting of thrombocytopenic, microangiopathic
hemolytic anemia, renal dysfunction, neurological signs and fever. Coexistence
of thrombotic thrombocytopenic purpura and Adult Onset Still's Disease (AOSD) is
extremely rare. We report a case of 18 year old girl with AOSD who developed
TTP. Neuroimaging of brain demonstrated white matter edema consistent with
reversible posterior leukoencephalopathy syndrome (RPLS). Complete recovery
occurred with prompt anti-hypertensive treatment and high dose immunoglobulin
infusions (IVIg). Plasma exchange is the standard of care and the first line
treatment for patient with TTP. We used IVIg alone in our case and this showed a
gratifying response. Use of IVIG before considering plasmapharesis is
justifiable or not requires randomized control clinical trials. This should
determine the optimal therapeutic strategies for TTP. A 21-year-old male presented to the emergency department after a 5-day history
of recurrent vomiting and decreased urine output. History revealed ingestion of
ibuprofen. During the diagnostic workup, the following was identified: white
blood cell count 13.4 (×10(3)/mcL), hemoglobin 11.9 (×10(6)/mcL) with an MCV of
73 fL, hematocrit 34% and platelets were 31,000/mcL, sodium of 130 mmol/L,
potassium of 5.1 mmol/L, chloride of 83 mmol/L, bicarbonate of 21 mmol/L, blood
urea nitrogen of 184 mg/dL and creatinine of 19.1 mg/dL. He was later diagnosed
with thrombotic thrombocytopenic purpura (TTP) based on the fact that he
presented with most components of the TTP pentad (except for fever), which
included altered mental status, acute kidney injury, thrombocytopenia, and
evidence of red cell fragmentation and his ADAMTS13 level was found to be less
than 10% prior to therapy. The patient then received plasma exchange, oral
corticosteroids, and hemodialysis, which led to a full recovery of platelet
count and renal function. BACKGROUND: Idiopathic thrombotic thrombocytopenic purpura (TTP) is a rare
hematological emergency characterized by the pentad of microangiopathic
hemolytic anemia, thrombocytopenia, neurological symptoms, renal injury, and
fever that is invariably fatal if left untreated. Prompt intervention with
plasma exchange minimizes mortality and is the cornerstone of therapy. Rare
reports have described "pseudo-TTP" driven by extreme hematologic abnormalities
resulting from deficiency of vitamin B12. Distinguishing between these entities
can pose a diagnostic and therapeutic challenge.
CASE PRESENTATION: A 77 year old female presented with altered mental status,
renal insufficiency, thrombocytopenia and evidence of microangiopathic hemolytic
anemia, suggesting TTP. Workup demonstrated macrocytosis and reticulocytopenia,
and B12 level was unmeasurably low. Other elements of her clinical presentation,
including volume loss and bleeding suggested a multifactorial pathogenesis could
be contributing to her laboratory abnormalities, reducing the likelihood that
she had TTP. The risks and benefits of treating aggressively with therapeutic
plasma exchange (TPE) for TTP were considered given the diagnostic
possibilities. The patient received TPE initially, with rapid de-escalation
after her clinical response suggested "pseudo-TTP" from B12 deficiency was the
driving the process. B12 supplementation corrected her hematologic abnormalities
and she remains well two years after presenting.
CONCLUSIONS: TTP is a rare condition with fatal consequences if left untreated.
Guidelines recommend TPE even if there is uncertainty about the diagnosis of
TTP. B12 deficiency is common, though not typically associated with severe
hematologic abnormalities. We compare the presenting characteristics of all
thirteen cases of pseudo-TTP reported in the literature with those from patients
in case series of TTP to suggest a set of parameters that can help clinicians
distinguish between pseudo-TTP and TTP and guide decision making regarding
intervention. Evaluation of all TTP cases should include a B12, methylmalonic
acid level and reticulocyte count. Reticulocytopenia suggests B12 deficiency.
Finally an LDH level above 2500 IU/L is relatively uncommon in TTP and should
suggest consideration of B12 deficiency. A diagnostic dilemma occurred when thrombotic microangiopathy developed during
pregcy. The diagnostic criteria of thrombotic microangiopathy include
thrombocytopenia (platelets <100) and microangiopathic haemolytic anaemia
(including thrombotic thrombocytopenic purpura and haemolytic-uraemic syndrome).
An urgent interdisciplinary approach is required to treat thrombotic
microangiopathy in pregcy to differentiate between thrombotic microangiopathy
and HELLP syndrome (haemolysis, elevated liver enzymes, low platelets).1 This
case presented with the pentad of thrombotic thrombocytopenic purpura: severe
thrombocytopenia (platelets 9 × 109/L), microangiopathic haemolytic anaemia
(reticular count 245 × 109/L (20-110)), LDH >5000 U/L (<425)), neurological
abnormalities (Glasgow Coma Scale 10/15), renal failure (creatinine 140 µmol/L
(<97)), fever (37.7℃). A Disintegrin And Metalloproteinase with a Thrombospondin
type 1 motif, member 13 (ADAMTS13) activity of less than 5% and anti-ADAMTS13
antibodies retrospectively confirmed the diagnosis of acquired idiopathic
thrombotic thrombocytopenic purpura in pregcy. The immediate management in
the Emergency Department with an interdisciplinary team of Consultant
Nephrologists, Intensivists, Haematologists and Obstetricians facilitated prompt
diagnosis resulting in immediate plasma exchange (PEX) and coordination of
semi-elective delivery of the foetus. Thrombotic thrombocytopenic purpura (TTP) is an acute, life-threatening illness
with disseminated platelet-rich thromboses of small vessels that variably
presents with the classic clinical "pentad" of microangiopathic hemolytic
anemia, thrombocytopenia, fever, altered mental status, and acute kidney injury.
Most cases are caused by an acquired autoantibody to ADAMTS13, a
metalloproteinase that cleaves large von Willebrand Factor (vWF) multimers. The
mainstay of treatment is daily therapeutic plasma exchange (TPE), sometimes with
adjunctive pharmacologic immunosuppression. TPE is generally continued until the
platelet count is greater than 150 × 103 /µL and the lactate dehydrogenase is
near normal for 2-3 consecutive days. Unfortunately, there is no clear guidance
for when thrombocytopenia is refractory for a prolonged period of time. The
following case describes such a scenario in which consecutive ADAMTS13 activity
and inhibitor levels were used to guide the decision to stop treatment with TPE
in a patient who failed to recover their platelet count. The autoimmune cytopenias are a group of disorders resulting primarily from
autoantibody-mediated destruction of blood cells, with variable clinical
sequelae depending on the severity and lineage affected. Disease presentation
ranges from an asymptomatic finding on a routine full blood count to an acutely
unwell patient suffering the clinical consequences of severe anaemia,
neutropenia or thrombocytopenia. The cytopenia may be primary or secondary to
underlying infectious, immune or maligt processes. Thrombotic
thrombocytopenic purpura (TTP) is a distinct, rare but potentially
life-threatening entity that classically but not invariably presents with a
pentad of acute onset haemolytic anaemia, thrombocytopenia, neurological
symptoms, renal impairment and fevers. Autoimmune cytopenias have formed a
recognised diagnostic entity for over 150 years yet continue to present a
challenge in medical practice due to heterogeneity in clinical presentation and
triggering factors, an incomplete understanding of underlying pathophysiology
and a lack of evidence-based therapeutic approaches. Thrombotic Thrombocytopenic Purpura (TTP) is a thrombotic microangiopathy
syndrome resulting from decrease or absence of "a disintegrin and
metalloproteinase with a thrombospondin type 1 motif member 13" (ADAMTS13). TTP
has been characterized by the classical pentad of thrombocytopenia, hemolysis,
fever, renal injury and neurological deficits, yet the patient may present with
any atypical symptom related to microthrombi formation in the microcirculation.
Here we present a rare case of a young patient with retrosternal chest pain and
myocardial injury as the first manifestation of TTP. We present a case of acute myeloid leukemia (AML) with myelodysplasia-related
changes that presented as thrombotic thrombocytopenic purpura (TTP). Our patient
presented with the classic pentad of TTP symptoms: anemia, thrombocytopenia,
fever, elevated creatinine, and altered mental status. After a failure to
respond to plasmapheresis therapy, we proceeded with a bone marrow biopsy and
fluorescent in situ hybridization, which supported formal diagnosis of AML with
myelodysplasia-related changes. Our case is an extremely rare presentation of a
rare condition, as there have been no reported cases of AML with
myelodysplasia-related changes presenting as TTP. Thrombotic thrombocytopenic purpura (TTP) is typically characterized by the
symptomatic pentad of fever, thrombocytopenia, microangiopathic hemolytic
anemia, neurologic abnormalities, and renal failure. Atypical TTP is the
diagnosis used to describe the subset of patients with TTP who present with
symptoms that deviate from the classic pentad. We report a case an 86-year-old
woman who presented to the emergency department complaining of chest pain for
one day. She was reportedly on antibiotics for sinus infection. Physical
examination revealed multiple bilateral superficial hematomas, predomitly on
her extremities. On admission, her lab values were as follows: platelet count of
6,000/cubic millimeter, hemoglobin of 10.4 grams/deciliter, leukocyte count of
5100 cells/cubic millimeter, total bilirubin of 2.3 milligrams/deciliter, and
troponin-I of 5.190 ograms/milliliter. Peripheral blood smear was normal and
did not reveal any schistocytes. The patient was admitted to the intensive care
unit with a diagnosis of a non-ST-elevation myocardial infarction and a presumed
diagnosis of immune thrombocytopenic purpura from antibiotic use. She was
treated with intravenous solumedrol and a high-intensity statin. On the third
day of her admission, the patient's mental functioning deteriorated and was
intubated to protect her airway. A second peripheral smear revealed
schistocytes, and subsequent laboratory studies supported the diagnosis of TTP.
Plasma exchange therapy was planned. However, the patient succumbed to cardiac
arrest before it could be initiated. The diagnosis was later confirmed with an
ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1
motif, member 13) assay. This case serves as an example of one of the many ways
in which TTP can present, and emphasizes the importance of considering TTP as a
differential diagnosis. |
What are organoids? | Organoids are 3D physiological in vitro structures that recapitulate morphological and functional features of in vivo tissues and offer significant advantages over traditional cell culture methods. | To generate a reliable preclinical model system exhibiting the molecular
features of salivary adenoid cystic carcinoma (ACC) whose biology is still
unclear due to the paucity of stable cell cultures. To develop new in vitro and
in vivo models of ACC, the techniques of organoid culture and patient-derived
tumor xenograft (PDX), which have attracted attention in other maligcies in
recent years, were applied. Tumor specimens from surgically resected salivary
ACC were proceeded for the preparation of PDX and organoid culture. The
orthotopic transplantation of patient-derived or PDX-derived organoids was
demonstrated into submandibular glands of NSG mice and those histology was
evaluated. PDX-derived organoid cells were evaluated for the presence of
MYB-mediated fusion genes and proceeded for in vitro drug sensitivity assay.
Human ACC-derived organoids were successfully generated in three-dimensional
culture and confirmed the ability of these cells to form tumors by orthotopic
injection. Short-term organoid cell cultures from two individual ACC PDX tumors
were also established that maintain the characteristic MYBL1 translocation and
histological features of the original parent and PDX tumors. Finally, the
establishment of drug sensitivity tests on these short-term cultured cells was
confirmed using three different agents. This is the first to report an approach
for the generation of human ACC-derived organoids as in vitro and in vivo cancer
models, providing insights into understanding of the ACC biology and creating
personalized therapy design for patients with ACC. Human cerebral organoids (HCOs) are an in vitro model of early neural
development, aimed at modelling and understanding brain development and
neurological disorders. In just a few years there has been rapid and
considerable progress in the attempt to create a brain model capable of
showcasing the characteristics of the human brain. There are still strong
limitations to address, including the absence of vascularization which makes it
difficult to feed the central layers of the organoid. Nevertheless, some
important features of the nervous system have recently been observed in cerebral
organoids: they manifest electrical activity (i.e. communication between
neurons), are sensitive to light stimulation and are able to connect to a spinal
cord by sending impulses that make a muscle contract. Recent data show that
cortical organoid network development at ten months resembles some preterm
babies EEG patterns. Although cerebral organoids are not close to human brains
so far due to their extremely simplified structure, this state of things gives
rise to ethical concerns about the creation and destructive experimental use of
human cerebral organoids. Particularly, one can wonder whether a human cerebral
organoid could develop some degree of consciousness and whether, under certain
conditions, it could acquire its own moral status with the related rights. In
this article, I discuss the conditions under which HCOs could be granted their
own moral status. For this purpose, I consider the hypothesis that HCOs might
develop a primitive form of consciousness and investigate the ways in which it
could be detected. In light of all this, I finally point out some cautionary
measures that could be introduced into research on and with human cerebral
organoids. The organoid model represents a major breakthrough in cell biology that has
revolutionised biomedical research. Organoids are 3D physiological in vitro
structures that recapitulate morphological and functional features of in vivo
tissues and offer significant advantages over traditional cell culture methods.
Liver organoids are of particular interest because of the pleiotropy of
functions exerted by the human liver, their utility to model different liver
diseases, and their potential application as cell-based therapies in
regenerative medicine. Moreover, because they can be derived from patient
tissues, organoid models offer new perspectives in personalised medicine and
drug discovery. In this review, we discuss the current liver organoid models for
the study of liver disease. |
List 3 therapeutic uses for botulism toxin. | Botulinum toxin injections are effective in relieving focal spasticity resulting from upper motor neuron injuries, migraine headaches, over active bladder and to relieve pain in the Sacroiliac Joint. | CONTEXT: Botulism is a potentially lethal paralytic disease caused primarily by
toxins of the anaerobic, spore-forming bacterium Clostridium botulinum. Although
botulinum toxin A is available by prescription for cosmetic and therapeutic use,
no cases of botulism with detectable serum toxin have previously been attributed
to cosmetic or therapeutic botulinum toxin injections. On November 27, 2004, 4
suspected botulism case-patients with a link to cosmetic botulinum toxin
injections were reported to the Centers for Disease Control and Prevention.
OBJECTIVE: To investigate the clinical, epidemiological, and laboratory aspects
of 4 suspected cases of iatrogenic botulism.
DESIGN, SETTING, AND PATIENTS: Case series on 4 botulism case-patients.
MAIN OUTCOME MEASURES: Clinical characteristics of the 4 case-patients,
epidemiological associations, and mouse bioassay neutralization test results
from case-patient specimens and a toxin sample.
RESULTS: Clinical characteristics of the 4 case-patients were consistent with
those of naturally occurring botulism. All case-patients had been injected with
a highly concentrated, unlicensed preparation of botulinum toxin A and may have
received doses 2857 times the estimated human lethal dose by injection.
Pretreatment serum toxin levels in 3 of the 4 case-patients were equivalent to
21 to 43 times the estimated human lethal dose; pretreatment serum from the
fourth epidemiologically linked case-patient was not available. A 100-microg
vial of toxin taken from the same manufacturer's lot as toxin administered to
the case-patients contained a toxin amount sufficient to kill approximately
14,286 adults by injection if disseminated evenly.
CONCLUSIONS: These laboratory-confirmed cases of botulism demonstrate that
clinical use of unlicensed botulinum toxin A can result in severe,
life-threatening illness. Further education and regulation are needed to prevent
the inappropriate marketing, sale, and clinical use of unlicensed botulinum
toxin products. Botulinum toxin poisoning has afflicted mankind through the mists of time.
However, the first incident of food-borne botulism was documented as late as the
18th century, when the consumption of meat and blood sausages gave rise to many
deaths throughout the kingdom of Württemberg in South Western Germany. The
district medical officer Justinus Kerner (1786--1862), who was also a well-known
German poet, published the first accurate and complete descriptions of the
symptoms of food-borne botulism between 1817 and 1822 and attributed the
intoxication to a biological poison. Kerner also postulated that the toxin might
be used for treatment purposes. In 1895, an outbreak of botulism in the small
Belgian village of Ellezelles led to the discovery of the pathogen "Clostridium
botulinum" by Emile Pierre van Ermengem. Modern botulinum toxin treatment was
pioneered by Alan B. Scott and Edward J. Schantz in the early 1970s, when the
type-A serotype was used in medicine to correct strabismus. Other preparations
of the type-A toxin were developed and manufactured in the United Kingdom,
Germany, and China, whereas a therapeutic type-B toxin was prepared in the
United States. To date, the toxin has been used to treat a wide variety of
conditions associated with muscular hyperactivity, glandular hypersecretions and
pain. Botulism is a severe neuroparalytic disease caused by toxins produced by several
Clostridium species. Botulinum toxin has been of concern to the US military and
its allies as a biowarfare weapon since World War II and, in more recent times,
by the Centers for Disease Control and Prevention (CDC) as a potential
bioterrorist threat to the public. The most effective means of defending against
the toxin is by inducing a protective immune response through vaccination.
Vaccination with an appropriate antigen will produce neutralizing antibodies
that will bind to and clear toxin from the circulation before it can enter nerve
cells and block neurotransmission. Immunity from botulism, however, has the
disadvantage of precluding an individual from realizing the potential benefits
of therapeutic botulinum toxin, if such a need were to arise. Botulinum toxin
has been used in the treatment of numerous neuromuscular, autonomic, and sensory
disorders since it was first approved for the management of strabismus and
blepharospasm by the Food and Drug Administration (FDA) in 1989. Notwithstanding
the value of the neurotoxin as a therapeutic drug, vaccines have been and will
continue to be an important line of defense for those who work with the toxin
(at-risk workers) and a select population of the military, law enforcement, and
first responders. The first vaccine used to protect against botulinum neurotoxin
was a chemically detoxified extract from Clostridium botulinum. A Pentavalent
botulinum toxoid (PBT) vaccine in service today is administered under an
Investigational New Drug (IND) application held by the CDC. Recombit subunit
vaccines are in development and a bivalent H(c) vaccine (rBV A/B (Pichia
pastoris)) is presently being evaluated in a phase II clinical trial. This
review focuses on botulism and the development of vaccines for its prevention. INTRODUCTION: Botulinum neurotoxin (BoNT) is probably the most potent biological
toxin that can affect humans. Since its discovery by Justinus Kerner, BoNT has
seen use in a wide range of cosmetic and non-cosmetic conditions such as
cervical dystonia, cerebral palsy, migraines and hyperhidrosis. We tried to
trace its history from its inception to its recent urological applications.
MATERIALS AND METHODS: Historical articles about botulinum toxin were reviewed
and a Medline search was performed for its urological utility. We hereby present
a brief review of historical aspects of BoNT and its applications in urology.
RESULTS: In 1793, the first known outbreak of botulism occurred due to 'spoiled'
sausage in Wildebad, Germany. The German physician and poet Justinus Kerner
published the first accurate description of the clinical symptoms of botulism
(sausage poison). He was also the first to mention its potential therapeutic
applications. In urology, BoNT has been used in bladder and urethral lesions
with varying degree of success. Recently, BoNT applications were explained for
prostatic disorders. BoNT applications in urology are in the treatment of
detrusor external sphincter dyssynergia, detrusor overactivity, detrusor
underactivity, spastic conditions of the urethral sphincter, chronic prostate
pain, interstitial cystitis, non-fibrotic bladder outflow obstruction (including
benign prostatic hyperplasia) and acute urinary retention in women.
CONCLUSION: Justinus Kerner is the godfather of botulism research. The role of
BoNT in urology has evolved exponentially and it is widely used as an adjuvant
in voiding dysfunction. In the future, its utility will broaden and guide the
urologist in managing various urological disorders. Sacroiliac joint (SIJ) pain is an important cause of lower back problems.
Multiple SIJ injection techniques have been proposed over the years to help in
the diagnosis and treatment of this condition. However, the SIJ innervation is
complex and variable, and truly intra-articular injections are sometimes
difficult to obtain. Different sacroiliac joint injections have shown to provide
pain relief in patients suffering this ailment. Various techniques for
intraarticular injections, sacral branch blocks and radiofrequency ablation,
both fluoroscopy guided and ultrasound guided are discussed in this paper. Less
common techniques like prolotherapy, platelet rich plasma injections and
botulism toxin injections are also discussed. BACKGROUND: Botulinum toxin injections are effective in relieving focal
spasticity resulting from upper motor neuron injuries. Doses approved in the
United States for onabotulinumtoxinA and incobotulinumtoxinA are up to
400 units, yet higher doses are often used.
OBJECTIVE: To determine differences in risk of adverse events when using higher
(>600 units) as compared to lower doses within clinically applicable categories;
the difference in adverse events between types of botulinum toxin-A, and any
association of the injection of cervical muscles with increased risk for adverse
events.
DESIGN AND SETTING: Retrospective analysis of injections performed over a 3-year
period at a freestanding rehabilitation hospital network.
PARTICIPANTS: Persons with spasticity or dystonia undergoing ona- and/or
incobotulinumtoxinA injections.
INTERVENTIONS: Not applicable.
MAIN OUTCOME MEASURES: Adverse events for injections were divided into the three
dose ranges (≤400 units, 401-600 units, or > 600 units).
RESULTS: 889 injections in 342 patients met inclusion criteria with 65% ≤400
units, 21% 401-600 units, and 14% >600 units. Adverse events were not
significantly increased in doses of 401-600 units relative to ≤400 units (OR
0.97, 95% CI 0.31, 2.98). Doses of toxin over 600 units were associated with
significantly increased relative risk of adverse events (OR 2.98, 95% CI 1.12,
8.13). There were no significant differences between adverse event rates for
onabotulinumtoxinA or incobotulinumtoxinA (P >.99). Inclusion of cervical
muscles in isolation did significantly increase the risk of adverse events (OR
4.21, 95% CI 1.15, 15.46).
CONCLUSION: Risk for adverse events were not significantly increased in doses of
ona- and/or incobotulinumtoxinA up to 600 units, suggesting that the current 400
units upper bound of approved dose may need to be reexamined. Doses above
600 units were found to increase the rate of adverse effects and clinical
benefit versus risk should be taken into account.
LEVEL OF EVIDENCE: III. PURPOSE: The significance of botulinum toxin to ophthalmologists is twofold.
Botulism, a medical emergency, frequently presents with ocular findings
including blurred vision, diplopia, ptosis, and photophobia as a result of the
neurotoxin produced by Clostridium botulinum. However, botulinum toxins also
have therapeutic uses for medical conditions including strabismus. The safety
and efficacy of Botulinum toxin A in patients with a history of botulism has not
been reported.
OBSERVATIONS: We report a 9-week-old infant, diagnosed with type B toxin
positive infant botulism treated with human botulism immune globulin, who
developed a large angle exotropia. The infant was treated with intramuscular
injections of botulinum toxin A to the extraocular muscles resulting in a
favorable initial response but ultimately required strabismus surgery. Clinical
manifestations and management of botulism are reviewed and botulinum toxin in
the treatment of pediatric strabismus is discussed.
CONCLUSIONS AND IMPORTANCE: This case demonstrates safe administration of
onabotulinumtoxinA to an infant with a history of antitoxin-treated botulism,
resulting in a transient improvement in control of infantile exotropia. |
What is the role of Tcf3 in the maintenance of pluripotency? | Tcf3 is an integral component of the core regulatory circuitry of ES cells, which includes an autoregulatory loop involving the pluripotency regulators. Tcf3 co-occupies promoters throughout the genome in association with the pluripotency regulators Oct4 and Nanog. Tcf3 down-regulation modulates the lineage differentiation potential of mouse embryonic stem cells through Wnt signaling. Tcf3 down-regulation is a necessary step towards Wnt-mediated suppression of differentiation. Depletion of Tcf3 enables the maintenance of undifferentiated mouse ESCs. | Self-renewal of rodent embryonic stem cells is enhanced by partial inhibition of
glycogen synthase kinase-3 (Gsk3; refs 1, 2). This effect has variously been
attributed to stimulation of Wnt signalling by β-catenin, stabilization of Myc
protein and global de-inhibition of anabolic processes. Here we demonstrate that
β-catenin is not necessary for embryonic stem cell identity or expansion, but
its absence eliminates the self-renewal response to Gsk3 inhibition.
Responsiveness is fully restored by truncated β-catenin lacking the
carboxy-terminal transactivation domain. However, requirement for Gsk3
inhibition is dictated by expression of T-cell factor 3 (Tcf3) and mediated by
direct interaction with β-catenin. Tcf3 localizes to many pluripotency genes in
embryonic stem cells. Our findings confirm that Tcf3 acts as a transcriptional
repressor and reveal that β-catenin directly abrogates Tcf3 function. We
conclude that Gsk3 inhibition stabilizes the embryonic stem cell state primarily
by reducing repressive influence on the core pluripotency network. Canonical Wnt signaling plays a rate-limiting role in regulating self-renewal
and differentiation in mouse embryonic stem cells (ESCs). We have previously
shown that mutation in the Apc (adenomatous polyposis coli) tumor suppressor
gene constitutively activates Wnt signaling in ESCs and inhibits their capacity
to differentiate towards ecto-, meso-, and endodermal lineages. However, the
underlying molecular and cellular mechanisms through which Wnt regulates lineage
differentiation in mouse ESCs remain to date largely unknown. To this aim, we
have derived and studied the gene expression profiles of several Apc-mutant ESC
lines encoding for different levels of Wnt signaling activation. We found that
down-regulation of Tcf3, a member of the Tcf/Lef family and a key player in the
control of self-renewal and pluripotency, represents a specific and primary
response to Wnt activation in ESCs. Accordingly, rescuing Tcf3 expression
partially restored the neural defects observed in Apc-mutant ESCs, suggesting
that Tcf3 down-regulation is a necessary step towards Wnt-mediated suppression
of neural differentiation. We found that Tcf3 down-regulation in the context of
constitutively active Wnt signaling does not result from promoter DNA
methylation but is likely to be caused by a plethora of mechanisms at both the
RNA and protein level as shown by the observed decrease in activating histone
marks (H3K4me3 and H3-acetylation) and the upregulation of miR-211, a novel
Wnt-regulated microRNA that targets Tcf3 and attenuates early neural
differentiation in mouse ESCs. Our data show for the first time that Wnt
signaling down-regulates Tcf3 expression, possibly at both the transcriptional
and post-transcriptional levels, and thus highlight a novel mechanism through
which Wnt signaling inhibits neuro-ectodermal lineage differentiation in mouse
embryonic stem cells. Cancer stem cells (CSCs) are thought to be responsible for tumor invasion,
metastasis, and recurrence. We previously showed that the pluripotency factor
Nanog not only serves as a novel biomarker of CSCs but also potentially plays a
crucial role in maintaining the self-renewal ability of liver CSCs. However, how
CSCs maintain Nanog gene expression has not been elucidated. Here, we
demonstrated that microRNA-449a (miR-449a) is overexpressed in poorly
differentiated hepatocellular carcinoma tissues, drug-resistant liver cancer
cells, cultured liver tumorspheres, and Nanog-positive liver cancer cells. The
upregulation of miR-449a in non-CSCs increased stemness, whereas the
downregulation of miR-449a in Nanog-positive CSCs reduced stemness. Furthermore,
transcription factor 3 (TCF3), a target of miR-449a, could downregulate Nanog
expression, and restoring TCF3 expression in miR-449a-expressing Nanog-negative
cells abrogated cellular stemness. These data establish that the
miR449a-TCF3-Nanog axis maintains stemness in liver CSCs. Although long noncoding RNAs (lncRNAs) are emerging as new modulators in the
fate decision of pluripotent stem cells, the functions of specific lncRNAs
remain unclear. Here, we found that telomeric RNA (TERRA or TelRNA), one type of
lncRNAs, is highly expressed in mouse embryonic stem cells (mESCs) but declines
significantly upon differentiation. TERRA is induced by the Wnt/β-catenin
signaling pathway and can reproduce its self-renewal-promoting effect when
overexpressed. Further studies revealed that T cell factor 3 ( TCF3) is a
potential downstream target of TERRA and mediates the effect of TERRA in mESC
maintece. TERRA inhibits TCF3 transcription, while enforced TCF3 expression
abrogates the undifferentiated state of mESCs supported by TERRA. Accordingly,
the transcripts of the pluripotency genes Esrrb, Tfcp2l1, and Klf2, repressed by
TCF3 in mESCs, are increased in TERRA-overexpressing cells. Our study therefore
highlights the important role of TERRA in mESC maintece and also uncovers a
mechanism by which TERRA promotes self-renewal. These data will expand our
understanding of the pluripotent regulatory network of ESCs. |
What pathological condition is MK-1602 used for? | MK-1602 has been assessed in clinical trials for the acute treatment of migraine. | AIM: The aim of this trial was to evaluate the efficacy and tolerability of
ubrogepant (MK-1602), a calcitonin gene-related peptide receptor antagonist
(CGRP-RA), for the acute treatment of migraine.
METHODS: This double-blind, placebo-controlled study randomized 834 participants
to treat one migraine attack with ubrogepant 1 mg, 10 mg, 25 mg, 50 mg, 100 mg,
or placebo in a 1:1 ratio. The co-primary endpoints were pain freedom and
headache response at two hours. The first primary hypothesis tested the
dose-response trend for two-hour pain freedom using a logistic regression model.
Subsequent hypotheses tested the effects of each dose on the co-primary
endpoints, using a closed sequential testing procedure to control for
multiplicity.
RESULTS: A total of 527 participants received ubrogepant and 113 received
placebo. A positive response trend in the proportion of participants achieving
two-hour pain freedom was demonstrated (p < 0.001). Ubrogepant 100 mg was
significantly superior to placebo for two-hour pain freedom (25.5% vs 8.9%) but
not for two-hour headache response. Per the prespecified multiplicity strategy,
this nonsignificant result precluded further formal hypothesis testing, although
the 50 mg and 25 mg doses demonstrated nominal significance over placebo for
two-hour pain freedom (unadjusted p < 0.05). Overall, adverse events were
similar between ubrogepant and placebo.
CONCLUSION: This trial supports ubrogepant's efficacy and provides further
evidence that CGRP-RAs are viable options for the acute treatment of migraine. Calcitonin gene-related peptide (CGRP) is a signaling neuropeptide released from
activated trigeminal sensory afferents in headache and facial pain disorders.
There are a handful of CGRP-targeted therapies currently in phase 3 studies for
migraine acute treatment or prevention. Currently, 4 monoclonal antibodies
targeting either the CGRP ligand or receptor are being studied for migraine
prevention: ALD403 (eptinezumab), AMG 334 (erenumab), LY2951742 (galcanezumab),
and TEV-48125 (fremanezumab). Meanwhile, 1 small-molecule CGRP receptor
antagonist (ubrogepant, MK-1602) is currently in phase 3 studies for the acute
treatment of migraine. Two of these anti-CGRP monoclonal antibodies are in
clinical trials for cluster headache prevention as well. Several other
small-molecular CGRP receptor antagonists are in earlier stages of development
for acute migraine treatment or prevention. In this review, we will discuss the
growing body of clinical trials studying CGRP-targeted therapies for migraine
and cluster headache. Merck & Co., Inc. (Kenilworth, New Jersey) has recently published an integrated
strategy for implementation of dried blood spots (DBS) in late-stage trials for
population pharmacokinetic (PK) modeling. We applied this strategy for another
late-stage clinical program: ubrogepant (MK-1602), a novel oral calcitonin
gene-related peptide receptor antagonist for acute treatment of migraine. At the
time of implementation, ubrogepant was entering phase 2 development. DBS was
implemented to acquire PK information proximal to an acute migraine event to
enable exposure-response modeling. The clinical endpoint was a spontaneous
event, which generally occurs outside a clinic visit. Thus, an innovative
feature of this trial was facilitating DBS in an outpatient setting. In vitro
and bioanalytical tests established initial method feasibility and suitability
for further evaluations in the clinic. A quantitative relationship was developed
between blood and plasma concentrations from concurrently collected samples in a
phase 1 (healthy subjects) and phase 2 (target patient population) study using
graphical and population PK approaches. This integrated information was
presented to the Food and Drug Administration for regulatory input. Following
regulatory concurrence, DBS was poised for use in further clinical studies.
Population PK modeling was used to dissect sources of variability contributing
to DBS collection in the outpatient setting. What has been learned from this
program has informed the broader integrated strategy of Merck & Co., Inc.
(Kenilworth, NJ) for DBS implementation in clinical trials and research to
improve the precision of PK data collected in an outpatient setting. Ubrogepant (MK-1602) is a novel, oral, calcitonin gene-related peptide receptor
antagonist in clinical development with positive phase III outcomes for acute
treatment of migraine. This paper describes the population exposure-response
(E-R) modeling and simulations, which were used to inform the phase III
dose-selection rationale, based on ~ 800 participants pooled across two phase
IIb randomized dose-finding clinical trials. The E-R model describes the placebo
and ubrogepant treatment effects based on migraine pain end points (2-hour pain
relief and 2-hour pain freedom) at various dose levels. Sensitivity analyses
were conducted to evaluate various assumptions of placebo response in light of
the high placebo response observed in one phase II trial. A population
pharmacokinetic model describing the effect of formulations was included in the
E-R simulation framework to assess potential dose implications of a formulation
switch from phase II to phase III. Model-based simulations predict that a dose
of 25 mg or higher is likely to achieve significantly better efficacy than
placebo with desirable efficacy levels. The understanding of E-R helped support
the dose selection for the phase III clinical trials. |
Is there an association of alterations in ADCY7 and ulcerative colitis? | Yes. Genome-wide analyses indicate a association between mutations in ACVR1 and ulcerative colitis due to loss-of-function mutations in ADCY7. | Author information:
(1)Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, UK.
(2)Division of Genetics and Rheumatology, Brigham and Women's Hospital, Harvard
Medical School, Boston, MA, USA.
(3)Program in Medical and Population Genetics, Broad Institute of Harvard and
MIT, Cambridge, MA, USA.
(4)Wellcome Trust Centre for Human Genetics, University of Oxford, Headington,
UK.
(5)Christ Church, University of Oxford, St Aldates, UK.
(6)Precision Medicine Exeter, University of Exeter, Exeter, UK.
(7)IBD Pharmacogenetics, Royal Devon and Exeter Foundation Trust, Exeter, UK.
(8)Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne.
(9)Department of Gastroenterology, Torbay Hospital, Torbay, Devon, UK.
(10)Department of Medicine, St Mark's Hospital, Harrow, Middlesex, UK.
(11)Nottingham Digestive Diseases Centre, Queens Medical Centre, Nottingham, UK.
(12)Institute of Human Genetics, Newcastle University, Newcastle upon Tyne, UK.
(13)Department of Medicine, Ninewells Hospital and Medical School, Dundee, UK.
(14)Genetic Medicine, Manchester Academic Health Science Centre, Manchester, UK.
(15)The Manchester Centre for Genomic Medicine, University of Manchester,
Manchester, UK.
(16)Gastrointestinal Unit, Wester General Hospital University of Edinburgh,
Edinburgh, UK.
(17)Translational Gastroenterology Unit, John Radcliffe Hospital, University of
Oxford, Oxford OX3 9DS, UK.
(18)Human Immunology Unit, Weatherall Institute of Molecular Medicine,
University of Oxford, Oxford OX3 9DS, UK.
(19)Gastroenterology & General Medicine, Norfolk and Norwich University
Hospital, Norwich, UK.
(20)Translational Gastroenterology Unit and the Department of Paediatrics,
University of Oxford, Oxford, United Kingdom.
(21)Paediatric Gastroenterology and Nutrition, Royal Hospital for Sick Children,
Edinburgh, UK.
(22)Child Life and Health, University of Edinburgh, Edinburgh, Scotland, UK.
(23)Inflammatory Bowel Disease Research Group, Addenbrooke's Hospital,
Cambridge, UK.
(24)Department of Medical and Molecular Genetics, Faculty of Life Science and
Medicine, King's College London, Guy's Hospital, London, UK.
(25)Sydney Brenner Institute for Molecular Bioscience, Faculty of Health
Sciences, University of Witwatersrand, South Africa.
(#)Contributed equally |
What is the mechanism of action of satralizumab? | Satralizumab is a humanized anti-interleukin-6 (IL-6) receptor monoclonal recycling antibody that has been approved for the treatment of neuromyelitis optica spectrum disorder (NMOSD). | Author information:
(1)Biopathologie de la Myéline, Neuroprotection et Stratégies Thérapeutiques,
INSERM U1119, Fédération de Médecine Translationnelle de Strasbourg (FMTS),
Université de Strasbourg, Bâtiment 3 de la Faculté de Médecine, 11 rue Humann,
67000, Strasbourg, France. [email protected].
(2)Département de Neurologie, Centre Hospitalier Universitaire de Strasbourg,
Avenue Molière, 67200, Strasbourg, France.
[email protected].
(3)Centre d'investigation Clinique, INSERM U1434, Centre Hospitalier
Universitaire de Strasbourg, 1 Place de l'Hôpital, 67000, Strasbourg, France.
[email protected].
(4)Laboratoire de Pharmacologie et Toxicologie Neurocardiovasculaire, Fédération
de Médecine Translationnelle, Faculté de Médecine, Université de Strasbourg, 11
rue Humann, 67000, Strasbourg, France.
(5)Biopathologie de la Myéline, Neuroprotection et Stratégies Thérapeutiques,
INSERM U1119, Fédération de Médecine Translationnelle de Strasbourg (FMTS),
Université de Strasbourg, Bâtiment 3 de la Faculté de Médecine, 11 rue Humann,
67000, Strasbourg, France.
(6)Département de Neurologie, Centre Hospitalier Universitaire de Strasbourg,
Avenue Molière, 67200, Strasbourg, France.
(7)Centre d'investigation Clinique, INSERM U1434, Centre Hospitalier
Universitaire de Strasbourg, 1 Place de l'Hôpital, 67000, Strasbourg, France. BACKGROUND: Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune
disease of the central nervous system and is associated with autoantibodies to
anti-aquaporin-4 (AQP4-IgG) in approximately two thirds of patients.
Interleukin-6 is involved in the pathogenesis of the disorder. Satralizumab is a
humanized monoclonal antibody targeting the interleukin-6 receptor. The efficacy
of satralizumab added to immunosuppressant treatment in patients with NMOSD is
unclear.
METHODS: In a phase 3, randomized, double-blind, placebo-controlled trial, we
randomly assigned, in a 1:1 ratio, patients with NMOSD who were seropositive or
seronegative for AQP4-IgG to receive either satralizumab, at a dose of 120 mg,
or placebo, administered subcutaneously at weeks 0, 2, and 4 and every 4 weeks
thereafter, added to stable immunosuppressant treatment. The primary end point
was the first protocol-defined relapse in a time-to-event analysis. Key
secondary end points were the change from baseline to week 24 in the
visual-analogue scale (VAS) pain score (range, 0 to 100, with higher scores
indicating more pain) and the Functional Assessment of Chronic Illness
Therapy-Fatigue (FACIT-F) score (range, 0 to 52, with lower scores indicating
more fatigue). Safety was also assessed.
RESULTS: A total of 83 patients were enrolled, with 41 assigned to the
satralizumab group and 42 to the placebo group. The median treatment duration
with satralizumab in the double-blind period was 107.4 weeks. Relapse occurred
in 8 patients (20%) receiving satralizumab and in 18 (43%) receiving placebo
(hazard ratio, 0.38; 95% confidence interval [CI], 0.16 to 0.88). Multiple
imputation for censored data resulted in hazard ratios ranging from 0.34 to 0.44
(with corresponding P values of 0.01 to 0.04). Among 55 AQP4-IgG-seropositive
patients, relapse occurred in 11% of those in the satralizumab group and in 43%
of those in the placebo group (hazard ratio, 0.21; 95% CI, 0.06 to 0.75); among
28 AQP4-IgG-seronegative patients, relapse occurred in 36% and 43%, respectively
(hazard ratio, 0.66; 95% CI, 0.20 to 2.24). The between-group difference in the
change in the mean VAS pain score was 4.08 (95% CI, -8.44 to 16.61); the
between-group difference in the change in the mean FACIT-F score was -3.10 (95%
CI, -8.38 to 2.18). The rates of serious adverse events and infections did not
differ between groups.
CONCLUSIONS: Among patients with NMOSD, satralizumab added to immunosuppressant
treatment led to a lower risk of relapse than placebo but did not differ from
placebo in its effect on pain or fatigue. (Funded by Chugai Pharmaceutical;
ClinicalTrials.gov number, NCT02028884.). PURPOSE OF REVIEW: This review summarizes recent insights into the pathogenesis
and therapeutic options for patients with MOG- or AQP4-antibodies.
RECENT FINDINGS: Although AQP4-IgG are linked to NMOSD, MOG-IgG-associated
diseases (MOGAD) include a broader clinical spectrum of autoimmune diseases of
the central nervous system (CNS). Details of membrane assembly of AQP4-IgG
required for complement activation have been uncovered. Affinity-purified
MOG-IgG from patients were shown to be pathogenic by induction of demyelination
when the blood--brain barrier (BBB) was breached and by enhancement of
activation of cognate T cells. A high-affinity AQP4-IgG, given peripherally,
could induce NMOSD-like lesions in rats in the absence of BBB breach.
Circulating AQP4-specific and MOG-specific B cells were identified and suggest
differences in origin of MOG-antibodies or AQP4-antibodies. Patients with
MOG-IgG show a dichotomy concerning circulating MOG-specific B cells; whether
this is related to differences in clinical response of anti-CD20 therapy remains
to be analyzed. Clinical trials of AQP4-IgG-positive NMOSD patients showed
success with eculizumab (preventing cleavage of complement factor C5, thereby
blocking formation of chemotactic C5a and membrane attack complex C9neo),
inebilizumab (depleting CD19 + B cells), and satralizumab (anti-IL-6R blocking
IL-6 actions).
SUMMARY: New insights into pathological mechanisms and therapeutic responses
argue to consider NMOSD with AQP4-IgG and MOGAD as separate disease entities. Introduction: Recent research has shown that IL-6 receptor (IL-6 R) inhibitors
like tocilizumab and satralizumab are effective in reducing the relapse rate in
patients with NMOSD.Areas covered: This review article explores current concepts
in NMOSD management and focuses on IL-6 R as a therapeutic target. The authors
delve into the biological and immunological role of IL-6 in the pathogenesis of
NMOSD. Further, the authors summarize the most recent findings on the use of
anti-IL-6 R monoclonal antibodies, tocilizumab and satralizumab, in the
treatment of NMOSD.Expert opinion: A better understanding of the role of
cytokines in NMOSD may provide the neurologist with novel therapies for this
disease. IL-6 R appears to be a central hub to NMOSD pathogenesis and a relevant
therapeutic target. BACKGROUND: Satralizumab, a humanised monoclonal antibody targeting the
interleukin-6 receptor, reduced the risk of relapse in patients with
neuromyelitis optica spectrum disorder (NMOSD) when added to immunosuppressant
therapy. This study assessed the safety and efficacy of satralizumab monotherapy
in patients with the disorder.
METHODS: In this phase 3, double-blind, placebo-controlled, parallel-group
trial, we enrolled adults aged 18-74 years with aquaporin-4 antibody
seropositive or seronegative NMOSD at 44 investigational sites in 13 countries.
Eligible participants had experienced at least one documented NMOSD attack or
relapse in the past 12 months and had a score of 6·5 or less on the Expanded
Disability Status Scale. Exclusion criteria included clinical relapse 30 days or
fewer before baseline. Participants were randomly assigned (2:1) to receive
satralizumab 120 mg or visually matched placebo subcutaneously at weeks 0, 2, 4,
and every 4 weeks thereafter. Taking immunosuppressants concomitantly was
prohibited. The primary endpoint was time to the first protocol-defined relapse,
based on the intention-to-treat population and analysed with stratification for
two randomisation factors (previous therapy for prevention of attacks and nature
of the most recent attack). Safety was assessed in all participants who received
at least one dose of satralizumab or placebo. The double-blind phase was due to
last until 44 protocol-defined relapses occurred or 1·5 years after random
assignment of the last patient enrolled, whichever occurred first; participants
could enter an open-label phase after the occurrence of a protocol-defined
relapse or at the end of the double-blind phase. The study is registered with
ClinicalTrials.gov, NCT02073279.
FINDINGS: 95 (57%) of 168 screened participants were randomly assigned to
treatment (63 to satralizumab; 32 to placebo) between Aug 5, 2014, and April 2,
2017. Protocol-defined relapses occurred in 19 (30%) patients receiving
satralizumab and 16 (50%) receiving placebo (hazard ratio 0·45, 95% CI
0·23-0·89; p=0·018). 473·9 adverse events per 100 patient-years occurred in the
satralizumab group, as did 495·2 per 100 patient-years in the placebo group; the
incidence of serious adverse events and adverse events leading to withdrawal was
similar between groups.
INTERPRETATION: Satralizumab monotherapy reduced the rate of NMOSD relapse
compared with placebo in the overall trial population, with a favourable safety
profile. The patient population included a ratio of aquaporin-4 antibody
seropositive and seronegative patients that was reflective of clinical practice.
Satralizumab has the potential to become a valuable treatment option for
patients with NMOSD.
FUNDING: Chugai Pharmaceutical (Roche). Satralizumab (Enspryng®), a humanized anti-interleukin-6 (IL-6) receptor
monoclonal recycling antibody, has been developed by Chugai Pharmaceutical and
Roche for the treatment of neuromyelitis optica spectrum disorder (NMOSD). In
June 2020, based on positive results from two pivotal phase III trials,
subcutaneous satralizumab received its first global approval in Canada for the
treatment of NMOSD in adults and children aged ≥ 12 years who are aquaporin 4
water channel autoantibody (AQP4-IgG) seropositive. Satralizumab was
subsequently approved in Japan, Switzerland and the USA. Satralizumab is under
regulatory review in the EU, and is undergoing clinical development in several
countries worldwide. This article summarizes the milestones in the development
of satralizumab leading to this first approval for the treatment of NMOSD. IMPORTANCE: Neuromyelitis optica (NMO - including NMO spectrum disorders
[NMOSD]) is a devastating disease. Eighty-three percent of patients with
transverse myelitic (TM) attacks and 67% of patients with optic neuritis (ON)
attacks have no or a partial recovery.
OBSERVATIONS: Up until recently, there was no proven agent to treat to prevent
relapses. The neuro-immunological community had a dearth of indicated agents for
NMOSD. We now have three agents indicated for the treatment of NMO including
(eculizumab [Soliris®]), an anti-C5 complement inhibitor, satralizumab
(ENSRYNG®), a monoclonal antibody against the IL-6 receptor (IL-6R) that blocks
B cell antibody production and inebilizumab (Uplinza®), a monoclonal antibody
that binds to the B-cell surface antigen CD19 with subsequent B and plasmablast
cell lymphocytolysis with decreasing antibody production. Autologous
hematopoietic stem cell bone marrow transplantation (AHSCBMT) has also been
used. How do we sequence NMO therapies with the understanding of the acuteness
and severity of the disease, the individual mechanism of action (MOA) and
rapidity of onset of action, onset of efficacy and long-term safety of each
agent?
CONCLUSIONS AND RELEVANCE: We might suggest the following sequence - 1st line
using eculizumab for rapid efficacy and stabilization without effect on the
acquired immune system followed by satrilizumab (long term immunomodulation).
Reserve inebilizumab (immunosuppressant) for breakthrough disease and salvage
the severe with AHSCBMT. In NMO, control the complement, transition to
modulation, and reserve suppression - and salvage the severe with AHSCBMT. Neuromyelitis optica spectrum disorder (NMOSD) is a rare and debilitating
autoimmune astrocytopathy with a predomitly relapsing disease course.
Satralizumab, a humanized monoclonal antibody, was designed to treat NMOSD by
targeting the IL-6 receptor. Satralizumab builds on positive experiences of
off-label use tocilizumab in recent years. Before 2019, no medications were
approved for the treatment of NMOSD. In 2020, satralizumab became the third
compound to enter the US market, adding to the complement inhibitor eculizumab
and the CD19 inhibitor inebilizumab. Here, we review the two randomized,
double-blind, Phase III trials that investigated the subcutaneous administration
of satralizumab as add-on treatment and monotherapy. Both studies revealed
positive effects concerning the reduction of relapse risk for AQP4 seropositive
NMOSD patients and generally good tolerability. Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune, inflammatory
disorder of the central nervous system that typically presents with recurrent
episodes of optic neuritis, longitudinally extensive myelitis, brainstem,
diencephalic, and cerebral syndromes. Up to 80% of NMOSD patients have a
circulating pathogenic autoantibody that targets the water channel aquaporin-4
(AQP4-IgG). The discovery of AQP4-IgG transformed our understanding of the
pathogenesis of the disease and its possible treatment targets. Monoclonal
antibodies targeting terminal complement (eculizumab), CD19 (inebilizumab), and
the interleukin-6 receptor (satralizumab) have demonstrated efficacy in NMOSD
attack prevention in recent phase 3 trials and have gained subsequent regulatory
approval in the USA and other countries. We aim to review the evidence
supporting the efficacy of these new drugs. |
Are mucin overexpression associated with disease? | Yes,
mucins are overexpressed in various malignancies and inflammations. | MUC1 is a membrane glycoprotein, which in adenocarninomas is overexpressed and
exhibits truncated O-glycosylation. Overexpression and altered glycosylation
make MUC1 into a candidate for immunotherapy. Monoclonal antibodies directed
against MUC1 frequently bind an immunodomit epitope that contains a single
site for O-glycosylation. Glycosylation with tumor carbohydrate antigens such as
the Tn-antigen (GalNAc-O-Ser/Thr) results in antibodies binding with higher
affinity. One proposed model to explain the enhanced affinity of antibodies for
the glycosylated antigen is that the addition of a carbohydrate alters the
conformational properties, favoring a binding-competent state. The
conformational effects associated with Tn glycosylation of the MUC1 antigen was
investigated using solution-state NMR and molecular dynamics. NMR experiments
revealed distinct substructures of the glycosylated MUC1 peptides compared with
the unglycosylated peptide. Molecular dynamics simulations of the MUC1
glycopeptide and peptide revealed distinguishing differences in their
conformational preferences. Furthermore, the glycopeptide displayed a smaller
conformational sampling compared with the peptide, suggesting that the
glycopeptide sampled a narrower conformational space and is less dynamic. A
comparison of the computed ensemble of conformations assuming random
distribution, NMR models, and molecular dynamics simulations indicated that the
MUC1 glycopeptide and aglycosylated peptide sampled structurally distinctly
ensembles and that these ensembles were different from that of the random coil.
Together, these data support the hypothesis that that conformational
pre-selection could be an essential feature of these peptides that dictates the
binding affinities to MUC1 specific antibodies. BACKGROUND: MUC1-glycoprotein is expressed at low levels and in fully
glycosylated form on epithelial cells. Inflammation causes MUC1 overexpression
and hypoglycosylation. We hypothesized that overexpression of hypoglycosylated
MUC1 would be found in postoperative Crohn's disease (CD) recurrence and could
be considered an additional biomarker of recurrence severity.
METHODS: We examined archived neo-terminal ileum biopsies from patients with
prior ileocecal resection who had postoperative endoscopic assessment of CD
recurrence and given a Rutgeerts ileal recurrence score. Consecutive tissue
sections were stained using 2 different anti-MUC1 antibodies, HMPV that
recognizes all forms of MUC1 and 4H5 that recognizes only
inflammation-associated hypoglycosylated MUC1.
RESULTS: A total of 71 postoperative CD patients were evaluated. There was
significant increase in MUC1 expression of both glycosylated/normal (P<0.0001)
and hypoglycosylated/abnormal (P<0.0001) forms in patients with severe
endoscopic CD recurrence (i3+i4), ileal score i2, compared with patients in
endoscopic remission (i0+i1). Results were similar regardless of anti-TNF-α use.
Although MUC1 expression and Rutgeerts scores were in agreement when
characterizing the majority of cases, there were a few exceptions where MUC1
expression was characteristic of more severe recurrence than implied by
Rutgeerts score.
CONCLUSIONS: MUC1 is overexpressed and hypoglycosylated in neo-terminal ileum
tissue of patients with postoperative CD recurrence. Increased levels are
associated with more severe endoscopic recurrence scores, and this is not
influenced by anti-TNF-α use. Discrepancies found between Rutgeerts scores and
MUC1 expression suggest that addition of MUC1 as a biomarker of severity of
postoperative CD recurrence may improve categorization of recurrence status and
consequently treatment decisions. Hepatolithiasis is a common disease that represents a serious health threat to
the Chinese population. The pathological mechanism underlying hepatolithiasis is
closely related to bacterial infections of the intrahepatic bile duct, followed
by chronic inflammation and the overexpression of mucin 5AC (MUC5AC). However,
the exact mechanism responsible for the lipopolysaccharide (LPS)‑induced
upregulation of MUC5AC has yet to be elucidated. Specificity protein 1 (Sp1) is
a ubiquitous transcription factor that plays a vital role in the regulation of a
number of genes that are responsible for normal cellular function.
microRNA (miR/miRNA)‑130b is a member of the miRNA family. miRNAs can bind to
the 3'‑untralsated region (3'‑UTR) of a target gene and influence its expression
levels. The present study found that LPS increases the expression of MUC5AC by
influencing Sp1 secretion. Chromatin immunoprecipitation‑quantitative PCR
experiments further verified three Sp1 binding sites in the MUC5AC promoter
sequence that can regulate the expression of MUC5AC. Further analysis
demonstrated that Sp1 expression was regulated by miR‑130b. Luciferase
experiments identified one miR‑130b binding site in the Sp1 3'‑UTR region.
In vivo experiments also confirmed the role of the miR‑130b‑Sp1‑MUC5AC signaling
pathway in the formation of biliary stones and indicated that this pathway may
provide targeted therapeutic strategies for the treatment of intrahepatic bile
duct stones. |
What are the 4 types of holoprosencephaly? | Holoprosencephaly is a rare congenital disorder which results from failure of cleavage or incomplete differentiation of the forebrain structures at various levels or to various degrees . Depending on the degree of involvement, it is classified into 4 types: Alobar, Semilobar, Lobar, and Middle interhemispheric fusion variant . | Five cases are presented to demonstrate the computed tomographic (CT) spectrum
of holoprosencephaly. The classifications of alobar, semilobar, and lobar types
A and B holoprosencephaly are each represented, with an additional case of
semilobar holoprosencephaly complicated by a subdural effusion. Holoprosencephaly is a rare congenital disorder which results from failure of
cleavage or incomplete differentiation of the forebrain structures at various
levels or to various degrees. Depending on the degree of involvement, it is
classified into 4 types: Alobar, Semilobar, Lobar and Middle interhemispheric
fusion variant. A male child was born to 28-year-old female at 34 weeks of
gestation. The mother on antenatal follow-up was detected to have a fetus with
multiple congenital anomalies on Ultrasonography (USG) done at 34weeks of
gestation. The baby died after 12 hours of birth. A complete autopsy was
performed. On external examination, multiple congenital anomalies were seen
including cleft lip and palate, absent nasal bridge, proptosis of right eye,
micropenis, left undescended testis, bilateral rocker bottom feet, omphalocele
and sacral meningomyelocele. Internal examination of the brain revealed
hydrocephalus and features of alobar holoprosencephaly. This case is presented
for its rarity. In addition, it is unusual for a fetus with alobar
holoprosencephaly to survive till term as this is the most severe type. Though
facial malformations are usually present in a case of holoprosencephaly, its
association with sacral meningomyelocele and omphalocele has rarely been
described in literature. |
Which yeast genes encode for condensin? | Smc2-Smc4 forms the core of the Saccharomyces cerevisiae condensin, which promotes metaphase chromosome compaction . Both SMC2 and SMC4 are essential for chromosome transmission in anaphase . Smc 2-8 suppresses catenanes accumulation, mitotic arrest and growth defects induced by histone depletion at semi-permissive temperature . | The condensin complex in frog extracts, containing two SMC (structural
maintece of chromosomes) and three non-SMC subunits, promotes mitotic
chromosome condensation, and its supercoiling activity increases during mitosis
by Cdc2 phosphorylation. Here, we report that fission yeast has the same
five-member condensin complex, each of which is essential for mitotic
condensation. The condensin complex was purified and the subunits were
identified by microsequencing. Cnd1, Cnd2, and Cnd3, three non-SMC subunits
showing a high degree of sequence conservation to frog subunits, are essential
for viability, and their gene disruption leads to a phenotype indistinguishable
from that observed in cut3-477 and cut14-208, known mutations in SMC4 and
SMC2-like subunits. Condensin subunits tagged with GFP were observed to alter
dramatically their localization during the cell cycle, enriched in the nucleus
during mitosis, but cytoplasmic during other stages. This stage-specific
alteration in localization requires mitosis-specific phosphorylation of the T19
Cdc2 site in Cut3. The T19 site is phosphorylated in vitro by Cdc2 kinase and
shows the maximal phosphorylation in metaphase in vivo. Its alanine substitution
mutant fails to suppress the temperature-sensitive phenotype of cut3-477, and
shows deficiency in condensation, probably because Cut3 T19A remains
cytoplasmic. Therefore, direct Cdc2 phosphorylation of fission yeast condensin
may facilitate its nuclear accumulation during mitosis. This work describes BRN1, the budding yeast homologue of Drosophila Barren and
Xenopus condensin subunit XCAP-H. The Drosophila protein is required for proper
chromosome segregation in mitosis, and Xenopus protein functions in mitotic
chromosome condensation. Mutant brn1 cells show a defect in mitotic chromosome
condensation and sister chromatid separation and segregation in anaphase.
Chromatid cohesion before anaphase is properly maintained in the mutants. Some
brn1 mutant cells apparently arrest in S-phase, pointing to a possible function
for Brn1p at this stage of the cell cycle. Brn1p is a nuclear protein with a
nonuniform distribution pattern, and its level is up-regulated at mitosis.
Temperature-sensitive mutations of BRN1 can be suppressed by overexpression of a
novel gene YCG1, which is homologous to another Xenopus condensin subunit,
XCAP-G. Overexpression of SMC2, a gene necessary for chromosome condensation,
and a homologue of the XCAP-E condensin, does not suppress brn1, pointing to
functional specialization of components of the condensin complex. We have characterized five genes encoding condensin components in Saccharomyces
cerevisiae. All genes are essential for cell viability and encode proteins that
form a complex in vivo. We characterized new mutant alleles of the genes
encoding the core subunits of this complex, smc2-8 and smc4-1. Both SMC2 and
SMC4 are essential for chromosome transmission in anaphase. Mutations in these
genes cause defects in establishing condensation of unique (chromosome VIII arm)
and repetitive (rDNA) regions of the genome but do not impair sister chromatid
cohesion. In vivo localization of Smc4p fused to green fluorescent protein
showed that, unexpectedly, in S. cerevisiae the condensin complex concentrates
in the rDNA region at the G2/M phase of the cell cycle. rDNA segregation in
mitosis is delayed and/or stalled in smc2 and smc4 mutants, compared with
separation of pericentromeric and distal arm regions. Mitotic transmission of
chromosome III carrying the rDNA translocation is impaired in smc2 and smc4
mutants. Thus, the condensin complex in S. cerevisiae has a specialized function
in mitotic segregation of the rDNA locus. Chromatin immunoprecipitation (ChIP)
analysis revealed that condensin is physically associated with rDNA in vivo.
Thus, the rDNA array is the first identified set of DNA sequences specifically
bound by condensin in vivo. The biological role of higher-order chromosome
structure in S. cerevisiae is discussed. The titan (ttn) mutants of Arabidopsis exhibit striking alterations in
chromosome dynamics and cell division during seed development. Endosperm defects
include aberrant mitoses and giant polyploid nuclei. Mutant embryos differ in
cell size, morphology and viability, depending on the locus involved. Here we
demonstrate that three TTN genes encode chromosome scaffold proteins of the
condensin (SMC2) and cohesin (SMC1 and SMC3) classes. These proteins have been
studied extensively in yeast and animal systems, where they modulate chromosome
condensation, chromatid separation, and dosage compensation. Arabidopsis
contains single copies of SMC1 and SMC3 cohesins. We used forward genetics to
identify duplicate T-DNA insertions in each gene. These mutants (ttn7 and ttn8)
have similar titan phenotypes: giant endosperm nuclei and arrested embryos with
a few small cells. A single SMC2 knockout (ttn3) was identified and confirmed by
molecular complementation. The weak embryo phenotype observed in this mutant may
result from expression of a related gene (AtSMC2) with overlapping functions.
Further analysis of titan mutants and the SMC gene family in Arabidopsis should
provide clues to chromosome mechanics in plants and insights into the regulation
of nuclear activity during endosperm development. To better understand the contributions that the structural maintece of
chromosome proteins (SMCs) make to condensin activity, we have tested a number
of biochemical, biophysical, and DNA-associated attributes of the Smc2p-Smc4p
pair from budding yeast. Smc2p and Smc4p form a stable heterodimer, the "Smc2/4
complex," which upon analysis by sedimentation equilibrium appears to reversibly
self-associate to form heterotetramers. Individually, neither Smc2p nor Smc4p
hydrolyzes ATP; however, ATPase activity is recovered by equal molar mixing of
both purified proteins. Hydrolysis activity is unaffected by the presence of
DNA. Smc2/4 binds both linearized and circular plasmids, and the binding appears
to be independent of adenylate nucleotide. High mole ratios of Smc2/4 to plasmid
promote a geometric change in circular DNA that can be trapped as knots by type
II topoisomerases but not as supercoils by a type I topoisomerase. Binding
titration analyses reveal that two Smc2/4-DNA-bound states exist, one disrupted
by and one resistant to salt challenge. Competition-displacement experiments
show that Smc2/4-DNA-bound species formed at even high protein to DNA mole
ratios remain reversible. Surprisingly, only linear and supercoiled DNA, not
nicked-circular DNA, can completely displace Smc2/4 prebound to a labeled,
nicked-circular DNA. To explain this geometry-dependent competition, we present
two models of DNA binding by SMCs in which two DNA duplexes are captured within
the inter-coil space of an Smc2/4 heterodimer. Based on these models, we propose
a DNA displacement mechanism to explain how differences in geometry could affect
the competitive potential of DNA. Proper chromatin condensation and sister chromatid resolution are essential for
the maintece of chromosomal integrity during cell division, and is in part
mediated by a conserved multisubunit apparatus termed the condensin complex. The
core subunits of the complex are members of the SMC2 (Structural Maintece of
Chromosomes) and SMC4 gene families. We have cloned an Arabidopsis gene,
AtCAP-E1, which is a functional ortholog of the yeast SMC2 gene. A second,
highly homologous SMC2 gene, AtCAPE-2, was identified by the Arabidopsis genome
project. SMC2 gene expression in Arabidopsis was correlated with the mitotic
activity of tissues, with high level expression observed in meristematic cells.
The two genes are differentially expressed with AtCAP-E1 accounting for more
than 85% of the total SMC2 transcript pool. The titan3 mutant is the result of a
T-DNA insertion into AtCAP-E1, but other than subtle endosperm defects, titan3
is viable and fecund. We identified a T-DNA insertion mutant of AtCAP-E2, which
showed no obvious mutant phenotype, indicating that the two genes are
functionally redundant. Genetic crosses were employed to examine the
consequences of reduced SMC2 levels. Both male and female gametogenesis were
compromised in double mutant spores. Embryo lethality was observed for both
double homozygous and AtCAP-E1(-/-), AtCAP-E2(+/-) plants; arrest occurred at or
before the globular stage and was associated with altered planes of cell
division in both the suspensor and the embryo. Down regulation of both genes by
antisense technology, as well as in AtCAP-E1(+/-), AtCAP-E2(-/-) plants results
in meristem disorganization and fasciation. Our data are consistent with the
interpretation that threshold levels of SMC2 proteins are required for normal
development and that AtCAP-E2 may have a higher affinity for its target than
AtCAP-E1. The structural organization of chromosomes is essential for their correct
function and dynamics during the cell cycle. The assembly of DNA into chromatin
provides the substrate for topoisomerases and condensins, which introduce the
different levels of superhelical torsion required for DNA metabolism. In
particular, Top2 and condensin are directly involved in both the resolution of
precatees that form during replication and the formation of the
intramolecular loop that detects tension at the centromeric chromatin during
chromosome biorientation. Here we show that histone depletion activates the
spindle assembly checkpoint (SAC) and impairs sister chromatid decatenation,
leading to chromosome mis-segregation and lethality in the absence of the SAC.
We demonstrate that histone depletion impairs chromosome biorientation and
activates the Aurora-dependent pathway, which detects tension problems at the
kinetochore. Interestingly, SAC activation is suppressed by the absence of Top2
and Smc2, an essential component of condensin. Indeed, smc2-8 suppresses
catees accumulation, mitotic arrest and growth defects induced by histone
depletion at semi-permissive temperature. Remarkably, SAC activation by histone
depletion is associated with condensin-mediated alterations of the centromeric
chromatin. Therefore, our results reveal the importance of a precise interplay
between histone supply and condensin/Top2 for pericentric chromatin structure,
precatees resolution and centromere biorientation. Structural maintece of chromosomes (SMC) protein complexes, including cohesin
and condensin, play key roles in the regulation of higher-order chromosome
organization. Even though SMC proteins are thought to mechanistically determine
the function of the complexes, their native conformations and dynamics have
remained unclear. Here, we probe the topology of Smc2-Smc4 dimers of the S.
cerevisiae condensin complex with high-speed atomic force microscopy (AFM) in
liquid. We show that the Smc2-Smc4 coiled coils are highly flexible polymers
with a persistence length of only ∼ 4 nm. Moreover, we demonstrate that the SMC
dimers can adopt various architectures that interconvert dynamically over time,
and we find that the SMC head domains engage not only with each other, but also
with the hinge domain situated at the other end of the ∼ 45-nm-long coiled coil.
Our findings reveal structural properties that provide insights into the
molecular mechanics of condensin complexes. |
What is another name for the drug AMG334? | AMG334 is also called erenumab. | PURPOSE OF REVIEW: The results of phase 2 randomized controlled trials for the
prevention of episodic and chronic migraine demonstrating the efficacy and
safety of four mAbs targeting the calcitonin gene-related peptide (CGRP) pathway
[ALD403 (eptinezumab), AMG334 (erenumab), LY2951742 (galcanezumab) and TEV48125
(fremanezumab)] have been published recently, and phase 3 trials are in process.
This development will change headache management fundamentally. We aim to
summarize and compare the phase 2 data.
RECENT FINDINGS: The change from baseline in the number of migraine days at the
end of treatment in high-frequency episodic migraine was -1 (at weeks 5-8), -1.1
(at weeks 9-12), -1.2 (at weeks 9-12) and -2.6 (at weeks 9-12) days for ALD403,
AMG344, LY2951742 and TEV48125 (225 mg), respectively. Number needed to treats
for responders and odds ratio for any adverse event were 4.7, 6.2, 4.0 and 4.0
and 1.09, 0.96, 1.07 and 1.05, respectively.
SUMMARY: All four CGRP antibodies display comparable efficacy that does not
differ significantly from that of the currently available oral antimigraine
drugs. However, their safety and tolerability profiles as well as low frequency
of administration looks promising but remains to be verified in long-term and
large-scale trials. Considerations related to pregcy, risk for cardiovascular
effects and cost are subject for further evaluation. |